Glossary

Terms used in the white papers, with the paper that explains each one.

A

Acclimation: Acclimation is the change in which a plant adapts to a higher light intensity during some weeks. The plant makes more chloroplasts, thicker leaf cuticles and a higher density of enzymes. Thus it can use the higher light intensity safely. Light acclimationreference
Acclimatization (hardening) also hardening: Acclimatization (hardening) is the task to make a plantlet from tissue culture stronger. You decrease the humidity and increase the light gradually. Thus the plantlet does not die in usual air. Tissue culturetissue culture
Action limit: An action limit is a value that you set before. When a reading is on the incorrect side of this value, a specified procedure is mandatory, and you must write the corrective action. An alert limit is a weaker limit that gives only an indication. Checks each dayoperationsprecision
Action threshold: An action threshold is a specified quantity of pests that starts a specified control procedure. For example, the quantity can be one pest that you see, or pests in more than 3% of a room. IPM SOPreference
Advisory / prescription: An advisory (prescription) is an output that gives the task, the setpoint, the time limit and the result that will occur. It tells you: 'do this, by this time, or this result will occur'. It is not only an alarm. Plant state dashboardreference
Air embolism: An air embolism is an air bubble in the stem after you cut it. It stops the uptake of water. You can prevent it if you put the cuttings in the substrate quickly and keep the ends of the cuttings wet. Cloningreference
Air-filled porosity: Air-filled porosity is the part of the pore space of a substrate that holds air immediately after the substrate drains. When the air-filled porosity increases, the water-holding capacity decreases. Substrates comparedreference
Airlock / gowning cascade: An airlock (gowning cascade) is a sealed room between two spaces. Its doors cannot open at the same time. Personnel put on more protective clothing in the room before they go into a space with a higher grade. GMP hash labreference
ALCOA+: ALCOA+ is a list of properties for data integrity. Records must be Attributable, Legible, Contemporaneous, Original and Accurate, plus Complete, Consistent, Enduring and Available. Compliance and traceabilityreference
Aliasing: Aliasing is an effect in data that occurs when the sampling is too slow. The slow sampling changes a fast cycle into a slow cycle that does not occur in the plant. Signal and noisereference
Alkalinity: Alkalinity is the capacity of water to neutralize acid. The capacity comes mostly from bicarbonates, and you give the value as ppm of calcium carbonate (CaCO3). Alkalinity is not the same as a high pH reading. pH controlreference
Annex 11 / PI 041: Annex 11 and PI 041 give the GMP requirements for computerized systems and data integrity (access control, audit trails, validation and backups). Compliance and traceabilityreference
Apical dominance: Apical dominance is the usual condition in which one primary top of a plant becomes higher than the side branches. Topping and LST stop apical dominance. Thus the growth of the plant is equal in all the branches. Vegetative stage lengthreference
AppDaemon: AppDaemon is the Python software environment that operates the primary decision loop of Crop Steering, which has approximately 5900 lines, on Home Assistant. F2 crop steeringprecision
AppDaemon engine: The AppDaemon engine is the automatic controller (file master_crop_steering_app.py). It reads the sensors and the settings, selects the phase of each row, and operates the hardware sequence. F2 crop steeringprecision
Aseptic technique: Aseptic technique is the method to keep bacteria, fungi and yeast out of your culture. It is the most important method in tissue culture. Tissue culturetissue culture
ASTM D8197: The industry standard for dry cannabis flower gives the range of 0.55 to 0.65 aw. Harvest, dry, trim, curereference
Auto-tick (check that the system completes) also Auto-tick: An auto-tick is a check item that the system records as done automatically, when its telemetry shows that the condition is correct. Thus the person does only the items that a sensor cannot examine. Checks each dayoperationsprecision
Autoflower seed: An autoflower seed is a seed with ruderalis genetics. The plant starts flowering automatically after a small number of weeks, and the photoperiod does not change this. Seeds and germinationreference
Auxin: An auxin is a type of plant hormone that increases the growth of roots. IBA is the best auxin for cannabis. Cloningtissue culturepropagation

B

Background drip baseline: The background drip baseline is the stable drip of the AC and the dehumidifier that the system finds at night. Then the system can subtract it from the total drain readings. Irrigation control · VRWEprecision
Baseline / trajectory: The baseline (trajectory) is the learned envelope for a specified cultivar, growth stage and photoperiod phase. The system calculates it from the data of your previous crops. Signal and noiseprecision
Batch / lot: A batch (lot) is one specified production run with one ID. The ID stays with the material in each transfer. Compliance and traceabilityreference
Batch / Lot Record: A batch (lot) record is the document that records all the materials, tasks, personnel, equipment, results and disposition for one batch (FRM-MF-004). REG-CU-001 holds these records together. Compliance and traceabilityreference
Batch release: Batch release is the controlled decision that a completed batch is safe and agrees with the specification. Test results and records give the data for the decision. The batch can go to a customer only after the decision. Compliance and traceabilityquality
Bicarbonate (HCO3-) also HCO3-: Bicarbonate is the primary compound in the water that causes alkalinity. It neutralizes the acid that you add, and thus the pH increases again. pH controlreference
Bioaerosol: Bioaerosol is a group of particles in the air that contain organisms. Examples are small pieces of skin with bacteria, fungal spores, and drops of liquid from a person who speaks or from a toilet flush. PPE and biosecurityhealth
Biocontrol / beneficial: A biocontrol, or beneficial organism, is an organism that you release to decrease the quantity of a pest. It can be a predator mite, a parasitoid wasp, or a microbe such as a fungus or a bacterium. IPM SOPreference
Biological control (biocontrol) also biocontrol: Biological control (biocontrol) is the procedure in which you release predators, which are insects or mites that eat pests. The predators do not cause damage to the plant. When no prey is available, the number of predators decreases. IPM SOPreference
Bleaching: Bleaching is a change of color in which the tissue becomes white or almost white. It occurs usually at the tips in the top of the canopy. Stress from light and oxidation causes it, and it is the result of photoinhibition that you can see. Light acclimationreference
Blocked-dripper guard: The blocked-dripper guard is a fail-safe. It stops the irrigation of a row for approximately 2 hours after too many emergency shots fail (default 4 in 30 min). Each row has an on/off switch for it. F2 crop steeringprecision
Boundary layer: The boundary layer is the thin layer of air that does not move, on each leaf surface. CO2 that goes in, and water vapor and heat that go out, must diffuse slowly across the layer. Thus the layer sets a limit on the rate of work of the leaf. Air that moves (approximately 0.3 to 1.0 m/s at the canopy) makes the layer thinner. In a dense canopy, a layer in air that does not move sets a limit of CO2 that no room sensor shows. Airflow and fansreference
Bti / Btk: Bti and Btk are types of the soil bacterium Bacillus thuringiensis. Bti (israelensis) kills the larvae of fungus gnats, and Btk (kurstaki) kills caterpillars. The two types kill the pest only when the pest eats them. IPM SOPreference
Bucking: Bucking is the procedure in which you cut the buds from the stem. You do it after trimming. Harvest, dry, trim, curereference
Bud rot (botrytis) also Bud rot: Bud rot (botrytis) is a gray mold that causes rot in buds with a high density, when the humidity is high. It is a primary risk in the last stage of flowering. Because of this risk, growers decrease the humidity. Mold riskreference
Bud set: Bud set is the time, approximately in weeks 3 to 4, when the pistils make small buds with a clear shape that become larger. Before this time, the pistils are at different positions. Flower week by weekreference
Buffer (buffering) also Buffer: Buffering is the resistance of a substrate to a change of pH. Soil has high buffering, and coco and hydroponics have almost no buffering. Thus you must control the pH of coco and hydroponics with more precision. pH controlreference
Buffer solution: A buffer solution is a liquid with a pH that you know accurately, for example 4.0 or 7.0. You use it to calibrate a pH pen. pH controlreference
Buffering: Buffering is the capacity of a substrate to absorb errors in the pH or in the strength of the nutrients. Thus the environment of the roots is more stable. Substrates comparedreference
Buffering capacity: Buffering capacity is the resistance of a substrate or of water to a change of pH. High buffering gives a small change of pH (soil). Low buffering gives a fast change of pH (coco, hydroponics). pH controlreference
Build back: Build back is the procedure in which you add minerals again to RO water or rainwater that has almost no minerals. The procedure is necessary because the plant must continue to get calcium, magnesium and some buffer. You usually add a CalMag supplement and the primary nutrients. Water qualityreference
Bulk EC: Bulk EC is the electrical conductivity of the mixture of the wet media (solids, water and air). The probe measures it directly in the range of 0-20000 microS/cm. Root-zone condition · TEROS-12reference
Bulking: Bulking is the middle phase of flowering (approximately weeks 5 to 7). In this phase, the mass of the buds increases at the highest rate. Flower week by weekreference
Burping: Burping is a short opening of a sealed container during curing. The opening lets moist air go out of the container and lets new air go into it. Harvest, dry, trim, curereference

C

C1D1: C1D1 (Class 1 Division 1) is a classification for areas where flammable solvent vapor can be in the air. It is for electrical equipment and rooms. These areas must have explosion-proof equipment and gas detection. GMP hash labreference
Cal-mag: Cal-mag is a supplement of calcium and magnesium. It is necessary when you use coco, to prevent the deficiency that the CEC of the coco causes. Substrates comparedreference
Calibration: Calibration is the adjustment of the reading of a sensor, to make it agree with the correct value for the substrate that you use. Without calibration, the percentage on the screen can be incorrect. Root-zone condition · TEROS-12sensors
Calm dashboard: A calm dashboard is a screen that shows exceptions. Usually the screen gives no information. It tells you only when there is important information. Plant state dashboardprecision
CalMag: CalMag is a supplement of calcium and magnesium, frequently with iron. You add it to water that has a small quantity of minerals, such as RO water, rainwater or very soft tap water. It prevents a deficiency of calcium and magnesium. Water qualityreference
Calvin cycle: The Calvin cycle is the half of photosynthesis that uses CO2. It changes the light energy that the plant absorbs into sugar. If the concentration of CO2 is too low, this stage cannot operate at the same rate as the light reactions. Light acclimationreference
Calyx: A calyx is one small part of the flower, in the shape of a drop. Many calyxes together make a bud. Flower week by weekreference
Cannabis ruderalis: Cannabis ruderalis is a strong subspecies of cannabis. Its genetics give autoflowers the automatic flowering that the photoperiod does not control. Seeds and germinationreference
CAPA: CAPA (Corrective And Preventive Action) is the standard procedure to repair a problem and to make sure that it does not occur again. It is one of the primary procedures of GMP. Compliance and traceabilityquality
CAPA (Corrective and Preventive Action) also CAPA: CAPA (Corrective and Preventive Action) is a procedure that starts from the root cause. Corrective action repairs a problem that occurred. Preventive action makes sure that a problem does not occur, or does not occur again. Compliance and traceabilityreference
Capacitance sensor: A capacitance sensor is a probe that measures the quantity of water in the substrate. It senses the electrical 'permittivity' of the substrate. Water changes the permittivity much more than soil or air does. Root-zone condition · TEROS-12sensors
Carbonate / bicarbonate: Carbonate and bicarbonate (CO3 and HCO3) are the compounds in solution that cause alkalinity. They neutralize the acid that you add. If the quantity is too large, they can cause lockout of calcium and magnesium. Water qualityreference
CCP (Critical Control Point) also CCP: A CCP (Critical Control Point) is a step in an operation, with a measured limit that prevents a specified hazard. It is a term from HACCP for control during the operation. GMP hash labreference
CEC (cation exchange capacity) also CEC: CEC (cation exchange capacity) shows how strongly a substrate holds cations, which are nutrient ions with a positive electric charge (in meq/100g). A high CEC gives more buffering of errors in the feed. Substrates comparedreference
Change Control: The standard procedure for each change that can change the quality of the product or the validated state is change control. In this procedure, you examine the change, give approval for it and then make it. Compliance and traceabilityreference
Channeling (preferential flow) also Channeling: Channeling (preferential flow) is water that flows straight down through the substrate. It does not touch the roots, and frequently it does not touch the sensor. Rockwool and crop steeringprecision
Chloramine: Chloramine is a disinfectant of chlorine and ammonia that is more stable than chlorine. It does not go out of the water as a gas when you keep the water in a container. To remove it, you must use a catalytic carbon filter or reverse osmosis. Water qualityreference
Chlorine: Chlorine is a disinfectant that suppliers frequently add to tap water. It moves from the water into the air as a gas in approximately 24 hours if you keep the water in a container with aeration. Chlorine can cause damage to the tips of the roots and to beneficial microbes at low concentrations. Water qualityreference
Chloroplast: A chloroplast is the structure in a cell that does photosynthesis. During acclimation, plants make more chloroplasts. Thus they can use a higher light intensity. Plant biology 101reference
Chlorosis: Chlorosis is the condition in which leaf tissue becomes yellow because the quantity of green chlorophyll decreases. Nutrient deficienciesreference
Cleanroom grade: A cleanroom grade shows the maximum number of airborne particles that a room can have. To control the contamination of the product, you use a grade with a smaller maximum number of particles, and you use gowning. GMP hash labqualityfacility
Cleanroom grade (CNC, D, C, B, A) also Cleanroom grade: A cleanroom grade shows how clean the air of a room is. In CNC, the air has no control, and no other grade has air as clean as Grade A. The grades agree with the ISO 14644 classes (D=ISO 8, C=ISO 7, A=ISO 5). GMP hash labreference
Clone: A clone is a copy of a plant that has the same genes as the plant. You can make a clone from a cutting or with tissue culture. Cloningpropagation
Closed loop: A closed loop is a control system in which the result goes back to cause the next step. The steps are: measure, select, adjust, and then measure the effect of the adjustment. The system does these steps again, continuously. The closed loopreference
Closed loop (with approval) also Closed loop: In a gated closed loop, the system does automatically only the tasks that have a low risk and a specified license. A person must give approval for each task that is permanent or has a high cost. The closed loopprecision
Closed-loop control: Closed-loop control is a system that measures a result, compares the result with the value that you want, and makes adjustments automatically. A thermostat is a typical example. The closed loopcontrol
CO2 supplementation: CO2 supplementation is a procedure in which you add carbon dioxide to the air. The concentration of carbon dioxide is then more than the usual value in the air (approximately 400 to 600 ppm). It agrees with a high light intensity, and it is necessary to prevent bleaching at intensities such as 1200 or 1500 µmol/m²/s. CO2 enrichmentreference
CoA (Certificate of Analysis) also CoA: A CoA (Certificate of Analysis) is the document that gives a list of the test results of a batch and compares them with the specification. You supply it at release. Lab testing and COAsreference
Coco coir: Coco coir is a substrate of coconut husk that you use as an alternative to soil. Water flows out of it quickly, and it changes quickly when you apply water. Coco and crop steeringprecision
Coefficient of variation (CV) also CV: The coefficient of variation (CV) shows how large the variation is, in relation to the average. For a batch of plants, the CV measures the noise (the differences between the plants) in your crop. Signal and noisereference
Cola: A cola is a large group of buds with a high density on a primary stem. The cola is usually the flower at the top of the plant, and it has the best growth. Flower week by weekreference
Common-cause variation: Common-cause variation is the usual small random change of a stable operation. It stays in the control limits. You must not adjust the operation for this variation. Signal and noisereference
Common-cause variation and special-cause variation: Common-cause variation is the usual small random change, and you do not adjust the operation for it. Special-cause variation is an unusual change, for example a point that is out of a limit or a sequence of points that is not random. An investigation is necessary for it. Signal and noisereference
Confidence: Confidence is the value that the system gives to show how accurate its estimate is at this time. When the confidence is high, the system can apply water. When the confidence is low, the system must be careful. Irrigation control · VRWEprecision
Control limits: Control limits are limits that you calculate from the data that you recorded for the operation (typically the mean ± 3 standard deviations). They divide the usual variation from the unusual variation. Signal and noisereference
Control limits (SPC) also SPC: Control limits are limits around the usual variation, and you calculate them with statistics. A reading in the limits is only noise, and a reading out of the limits is a signal for a correction. SPC is the short name of 'statistical process control'. Signal and noisecontrol
Cotyledons: Cotyledons, or seed leaves, are the two rounded leaves of the embryo that you see first. They contain nutrients and supply them to the seedling. Seeds and germinationreference
Coupled system: A coupled system is a system in which a change to one control changes some other controls at the same time. Thus no lever operates independently. Grow room systemsreference
Crop steering: Crop steering is a method to cause a plant to make more vegetative growth (leaves) or more generative growth (flowers and fruit). You control the irrigation, the climate and the light. Coco and crop steeringcrop steering
Crop Steering AI (CS) also CS: Crop Steering AI (CS) is an irrigation system with 4 phases. It uses sensor data, and it has control for each zone, EC logic and ML prediction. It is the irrigation controller that operates at this time. F2 crop steeringprecision
Cross-contamination: Cross-contamination is the movement of contamination from a dirty area or item to a clean area or item. For example, a person goes from the flower area back to the propagation area and does not put on a gown again. PPE and biosecurityoperationshealth
Culling: Culling is the procedure in which you divide the clones into groups before transplant. You remove the clones that are weak or do not have roots. The groups are keepers, rejects and kills. Cloningreference
Curing: Curing is the procedure in which a completed batch becomes stable, with the same water activity in all the flower. During curing, you keep the terpenes and prevent mold. Harvest, dry, trim, curereference
Cutting: A cutting is a shoot that you cut from a plant. It makes roots and becomes a clone. The terms cutting and clone are interchangeable. Cloningreference
Cytokinin: A cytokinin is a type of plant hormone that increases the growth of shoots and buds. The examples are meta-topolin, BAP and TDZ. Tissue culturetissue culture

D

Damping-off: Damping-off is a fungal disease (Pythium, Fusarium, Rhizoctonia). It causes rot in the seedling at the level of the soil, and it usually kills the seedling. Seeds and germinationreference
Dead-band: A dead-band is the tolerance range in which a controller does not make a correction. If the dead-band is too small, the equipment makes too many adjustments (hunting). Signal and noisereference
Defanning / Defoliation: Defanning (defoliation) is the removal of selected large fan leaves. It opens the canopy. Thus light goes into the canopy and air flows through it. Defoliation and trainingreference
Deficiency: A deficiency is the condition in which the plant does not get a sufficient quantity of a nutrient. The plant has less color, becomes yellow, and its growth is slow. Nutrient deficienciesreference
Defoliation: Defoliation is the removal of selected leaves. Thus more light and more air go into the canopy. Defoliation and trainingreference
Dehumidification load: The dehumidification load is the quantity of water that a room must remove from the air each day to keep its humidity target. The transpiration of the canopy sets the load, and at a high light intensity the load is frequently the limit of the yield. The unit is liters or US pints each day (1 liter is approximately 2.1 pints), and a dense flowering canopy can transpire some liters for each square meter each day. HVAC and dehumidifiersreference
Deviation: A deviation is each difference from the approved procedure in the documents. You must record it and do an investigation. Compliance and traceabilityreference
Digital twin: A digital twin is a 3D model connected to the data of sensors in the facility. Thus it shows the temperature, the humidity and the equipment status at this time. 3D facility modelprecision
Dilution: Dilution is the procedure in which you mix a material equally in a large volume of water. Thus the concentration is low. This low concentration makes it safe to add Part B after Part A. Mix nutrientsreference
Dissolved oxygen (DO) also DO: Dissolved oxygen (DO) is the quantity of oxygen in solution in water, and the roots must have it. DO decreases when the temperature of the water increases, from approximately 5 to 6 ppm at 20 °C to 3 to 4 ppm at 26 °C. A low DO increases the risk of root disease. Deep water culturereference
DLI: DLI (daily light integral) is the total quantity of light that a plant receives and can use in one day, in mol/m²/day. You calculate DLI from the light intensity (PPFD) and the hours of light. Thus two different intensities can give the same DLI with different photoperiods. Basic lightingreference
DLI (Daily Light Integral) also DLI: DLI (daily light integral) is the total number of PAR photons that a surface receives in one day, in moles for each square meter (mol/m2/day). DLI = PPFD x seconds of light in each day / 1,000,000. It is the dose that has the largest effect on the yield. Basic lightingreference
Dome: A dome is a transparent plastic lid for humidity. You put it on a clone tray to keep moisture around the cuttings that do not have roots. Cloningreference
Draw call: A draw call is one instruction to the graphics card to show an object. When the number of draw calls is smaller, the model is faster (keep the number less than approximately 300). 3D facility modelprecision
Drench: A drench is a treatment that you apply to the substrate and the root zone, and not to the foliage. IPM SOPreference
Drift: Drift is a slow sensor error that is always in the same direction, and it shows a trend that does not occur in the plant. It is the dangerous type of noise. Only calibration and a check with other data can remove it. Signal and noisereference
Dry-to-wet ratio: The dry-to-wet ratio is the last dry weight as a fraction of the initial wet weight. It is approximately 10% in the source data. Harvest, dry, trim, curereference
Dryback: Dryback is the quantity by which the moisture in the root zone decreases between irrigations. A grower sets the dryback to cause generative growth or vegetative growth in the plant. Coco and crop steeringcrop steering
Dryback %: Dryback % is the size of a dryback, in percentage points of water content. It is the peak of each day minus the next trough. For example, 78% to 58% is a dryback of 20 points. Coco and crop steeringcrop steering
DUL (drained upper limit) / container capacity: DUL (drained upper limit), or container capacity, is the quantity of water that a container holds after free drainage stops. It is a value that you find for each pot, and it is not a constant value for the substrate. It changes slowly when the roots become larger. Root-zone condition · TEROS-12reference
DWC (deep water culture) also DWC: DWC (deep water culture) is hydroponics in which the roots hang in nutrient water with oxygen, and there is no solid medium. An air pump supplies the oxygen. Deep water culturereference

E

EC: EC is electrical conductivity. It shows the strength of the nutrients in the feed water, in mS/cm. Mix nutrientsreference
EC (electrical conductivity) also EC: EC gives an estimate of the quantity of fertilizer salt that is in solution in the root zone. When the EC is higher, the feed is stronger. Root-zone condition · TEROS-12crop steeringsensors
EC ratio: The EC ratio is the measured EC divided by the target EC. When the ratio is more than 1, the salt strength is too high (apply more water to dilute). When the ratio is less than 1, the salt strength is too weak (apply less water). F2 crop steeringprecision
Efficacy (umol/J) also umol/J: Efficacy is the number of PAR photons that a fixture makes for each joule of electricity (umol/J). It is the primary number for the efficiency when you compare lights. Good LEDs have approximately 2.7 to 3.0 umol/J, HPS lights have approximately 1.7 to 1.9, and CMH lights have approximately 1.3 to 1.9. Basic lightingreference
EM (Environmental Monitoring) also EM: EM (Environmental Monitoring) is the procedure to get samples of non-viable particles, viable air, surfaces and personnel. You compare the results with the alert limits and the action limits. GMP hash labreference
Embryo: The embryo is the very small plant in the seed. It contains a root, two cotyledons and a shoot. Seeds and germinationreference
Endophyte: An endophyte is a microbe that is in the tissue of a plant that looks in good condition. It is the contaminant that you cannot easily remove in tissue culture, because bleach on the surface cannot touch it. Tissue culturetissue culturedisease
Entomopathogenic nematodes: Entomopathogenic nematodes are very small worms, for example Steinernema feltiae. You apply them as a drench to the substrate. They are parasites of fungus gnat larvae, and they kill the larvae. IPM SOPreference
ESPHome: ESPHome is the firmware platform that operates the hardware sensors and some switches. It sends the data to Home Assistant. DIY plant-biosignal sensorprecision
EWMA: EWMA is the exponentially-weighted moving average. It is a rolling average that gives more weight to the newest readings. Thus it has less lag for the same smoothing. Signal and noisereference
Exclusion: Exclusion is the procedure in which you control the persons and the items that go into a room with pests. It stops pests that move from one room to a different room. IPM SOPreference
Explant: An explant is a small piece of a plant. You cut it from the plant and put it in the culture vessel to start a new culture. Tissue culturetissue culture
Extrude: To extrude is to extend a flat 2D shape (for example, the shape of a floor) up, to give it thickness or height. 3D facility modelprecision

F

Fail-safe read: In a fail-safe read, the engine cannot find the condition of the primary arm switch. The engine then uses the condition OFF and does not apply a shot. Thus a condition that is not synchronized cannot cause the engine to operate without data. F2 crop steeringprecision
Fan leaves: Fan leaves are the large leaves that have a small number of trichomes. You remove them by hand at the start of trimming. Harvest, dry, trim, curereference
Far-red: Far-red is light of approximately 700 to 750 nm, immediately after the PAR range. Phytochrome senses far-red light, and far-red light can make the plant sense the start of the night more quickly. Far-red light causes some stretch of the stem, and high doses of it can decrease the density of the buds. Basic lightingreference
Feedback: In feedback, a system uses the measured result of an operation to select the next operation. Feedback is the primary part of each closed-loop system, which makes corrections automatically. The closed loopcontrol
Feminized seed: A feminized seed is a seed that a breeder makes to give almost only female plants. Thus it is not necessary to identify and remove male plants. Seeds and germinationreference
Field capacity: Field capacity is the maximum VWC that the medium can hold before water flows out. The default maximum is 70%. Substrates comparedprecision
Field capacity / substrate EC: The substrate EC is the concentration of salt in the substrate of the root zone. The Athena guide gives targets for each stage, for example 3 to 5 in the vegetative stage. You use the mixed feed to increase the substrate EC to these targets. Root-zone condition · TEROS-12reference
FIM: FIM is a topping in which you cut most of the top tip but not all of it. FIM can make some new tops. A topping that removes all the tip makes only two new tops. Vegetative stage lengthreference
Fit-out: The fit-out is the equipment and furniture in the bare shell of the building: benches, lights, dehumidifiers, tanks and racks. 3D facility modelprecision
Flip (12/12) also Flip: The flip is the change of the grow light timer to 12 hours on and 12 hours off. The change causes flowering in photoperiod plants. Flower week by weekreference
Floor plan: A floor plan is a flat drawing from an architect. It shows the walls, doors and rooms from above, usually with dimensions in millimeters. 3D facility modelprecision
Florigen: Florigen is a protein that moves in the plant and is the flowering signal. The leaves make it when the nights are sufficiently long. It moves to the growth tips, and it causes them to make buds and not leaves. Basic lightingreference
Flush: A flush is the procedure in which you apply water that flows through the substrate and removes the salts that collect. The water has the correct pH, and it has no fertilizer or a small quantity of fertilizer. Thus the root zone is in its initial condition again. Ripening and harvestreference
Foliar spray: A foliar spray is a liquid treatment that you apply to the leaves and the stems, and not to the root zone. IPM SOPreference
Fomite: A fomite is an object that holds microbes and moves them to a different object. Examples are a phone, a pen, a tool or a handle. Hands move contamination from fomites to the crop. PPE and biosecurityhealth
FOV cone: An FOV cone is a transparent shape that shows the area in the field of view of a camera. The floor out of all the cones is a possible blind spot. 3D facility modelprecision
Frass: Frass is waste from insects and small pieces of material. During scouting, you can see frass as one of the first signs of pests. Pest ID and controlreference
Full pot (DUL, drained upper limit) also Full pot: The full pot (DUL, drained upper limit) is the maximum quantity of water that a pot can hold after drainage. Irrigation control · VRWEprecision

G

GACP: GACP (Good Agricultural and Collection Practice) is the standard for cultivation and drying, before the GMP facility. It supplies biomass that agrees with GMP to the facility. Compliance and traceabilityreference
GACP (Good Agricultural and Collection Practice) also GACP: GACP (Good Agricultural and Collection Practice) is the standard for the cultivation and collection of the starting material of medicinal cannabis. In this standard, the material is a plant crop before it becomes a medicine. Compliance and traceabilityreference
GDP (Good Documentation Practice) also GDP: GDP (Good Documentation Practice) is a group of procedures to make and to correct records. You make a record at the time of the task, and you cannot erase it. A correction is one line through the error, with initials, a date and a cause, and the initial entry stays easy to read. Compliance and traceabilityreference
Genealogy / traceability: Genealogy (traceability) is the record that connects each completed unit to its source lots, operators, equipment and conditions, forward and back. It makes possible a recall of specified lots only. Compliance and traceabilityreference
Generalist and specialist predator: A generalist predator eats many types of pest and also eats pollen. It stays in the crop when there is no prey. A specialist predator eats one type of pest quickly, but its number decreases when there is no prey of that type. IPM SOPreference
Generative and vegetative: The two growth modes of a plant are vegetative growth (leaves, stems and size) and generative growth (flowers, fruit and density). Crop steering changes the balance between the two modes. Coco and crop steeringcrop steering
Germination: Germination is a sequence in which a seed in dormancy absorbs water and becomes active. Then the seed extends its first root and its first shoot. Seeds and germinationreference
Germination rate: The germination rate is the percentage of the seeds in a batch that germinate. Seeds and germinationreference
glTF: glTF is a standard 3D file format. You use it to import models with much detail, which you make in tools (for example Blender), and to export the building. 3D facility modelprecision
GMP (good manufacturing practice) also GMP: GMP is a quality system of procedures and records. It makes sure that a manufacturer makes products safely, with the same result each time, and with records that let you trace each product. Compliance and traceabilityquality
Gowning / de-gowning: Gowning is the procedure to put on protective clothing, and de-gowning is the procedure to remove it. You do the two procedures in a specified sequence at the clean/dirty line, and thus contamination does not go across it. You put on the gown from the top to the bottom, and you remove it in the opposite sequence, with the dirtiest item first. PPE and biosecurityoperationshealth
Grams per liter (g/L) also g/L: Grams for each liter (g/L) is the unit of dose for nutrient powders. To find the grams to weigh, multiply the g/L on the label by the volume of the tank. For example, multiply by 50 for a tank of 50 L. Mix nutrientsreference

H

Hardening off: Hardening off is the procedure in which you open the vents gradually and remove the dome. Thus the clones with roots adapt to drier room air before transplant. Cloningreference
Hardness: Hardness is the quantity of calcium and magnesium in solution in water. You give it in ppm CaCO3 or in grains for each gallon (1 GPG is 17.1 mg/L). Soft water has less than approximately 1 GPG, and very hard water has more than approximately 10.5 GPG. Water qualityreference
Hermaphroditism (hermie) also hermie: Hermaphroditism is the condition in which a female plant in stress makes male parts. The pollen from the male parts pollinates the plant, and the buds then have seeds. A frequent cause is a light leak in the period of darkness. Flower week by weekreference
Hierarchy of controls: The hierarchy of controls is the sequence of steps that the regulations give for the control of risk. The steps are: remove the risk, replace it, isolate it, use engineering controls, use administrative controls, and last, use PPE. PPE and biosecurityoperations
Hilhorst model: The Hilhorst model is a method from the year 2000. It gives an estimate of the pore-water EC from the bulk EC, the VWC and the temperature. You can use it, but its sensitivity is approximately +/-20%, and it is not correct when the VWC is less than 0.10 m3/m3. Root-zone condition · TEROS-12reference
Home Assistant: Home Assistant is open-source software, with no cost, for home automation. It operates the dashboards, automations and integrations that are in this paper. Irrigation manualprecision
Honeydew: Honeydew is tacky waste with sugar from aphids and whitefly. It is on the leaves, and black sooty mold occurs on it. Pest ID and controlreference
Hop Latent Viroid (HpLVd) also HpLVd: Hop Latent Viroid (HpLVd) is a very small loop of RNA that is smaller than a virus. It causes 'dudding' in cannabis. Plants with dudding stay small and make smaller buds, and they contain much smaller quantities of cannabinoids and terpenes. Mother plantsdisease
Humidity dome: A humidity dome is a transparent lid that you put above seedlings. It keeps the moisture near the plants and keeps the humidity high while the roots are very small. Seeds and germinationreference
Hunting: Hunting is an oscillation in a feedback loop. The loop makes corrections that are too large, in one direction and then in the other direction, and it does not become stable. The cause is frequently noise in the input or a tuning that is too sensitive. Signal and noisereference
Hydroponics: Hydroponics is a method in which the roots are in a nutrient solution, or in an inert medium that receives it, and not in soil. The pH of the solution must have a value that is acid but near neutral. You must control the pH with precision. Substrates comparedreference
Hyperhydricity (vitrification) also vitrification: Hyperhydricity (vitrification) is a problem of tissue culture. A culture with this problem makes glassy shoots that contain too much water and are larger than usual. The shoots make roots badly, do not acclimatize correctly, and usually die when you transplant them. Tissue culturetissue culture

I

ICH Q9 / Q10: ICH Q9 and ICH Q10 are international harmonization guidelines. Q9 is for Quality Risk Management and Q10 is for the Pharmaceutical Quality System. GMP hash labreference
Imbibition: Imbibition is the first step of germination. In this step, the seed absorbs water and becomes larger. Seeds and germinationreference
Immobile nutrient: An immobile nutrient is a nutrient that stays where the plant first puts it, and the plant cannot move it to a different position. The immobile nutrients are Ca, S, Fe, Mn, Zn, B, Cu and Mo. As a result, the deficiency shows first on the new growth at the top of the plant. Nutrient deficienciesreference
Implementation intention: An implementation intention is an if-then instruction that attaches a task to a specified time and location. For example, at lights-on the AM technician does X. It makes the person do the task 2 to 3 times more frequently. Checks each dayoperations
In vitro: In vitro is a Latin term for 'in glass'. It is the term for all that occurs in the culture vessel without microbes. The opposite term is ex vitro, which is for all that occurs out of the vessel. Tissue culturetissue culture
Indexing: Indexing is a laboratory test of a plant, for example with RT-qPCR, to make sure that the plant has no specified disease. The test shows that the plant is clean. Tissue culturetissue culturedisease
Inert medium: An inert medium is a substrate, such as rockwool, that does not contain nutrients. Thus the plant gets only the nutrients that you apply in the feed. Substrates comparedreference
Inference layer: The inference layer is the part of the system that calculates estimates of values that you cannot measure directly (plant stress, transpiration and vigor). It uses values that you can measure. Plant state dashboardprecision
Instancing: Instancing is the method to show many objects that are the same, for example 210 plants, in one batch and not one at a time. It is the primary method to keep the model fast. 3D facility modelprecision
Integrated Pest Management (IPM) also IPM: Integrated Pest Management (IPM) is a loop of tasks that you do again and again. You examine the pests, you make a decision, and you control the pests. You use the weakest method that is sufficient, and you use a stronger method only when it is necessary. IPM SOPreference
Internode: An internode is the length of bare stem between two nodes. Cloningreference
Interveinal chlorosis: Interveinal chlorosis is chlorosis between the veins of the leaf. The veins stay green. You see this condition with problems of magnesium, iron and manganese. Nutrient deficienciesreference
Inverse-square law: The inverse-square law is a relation in which the light intensity decreases with the square of the distance. When the gap between the fixture and the canopy becomes two times larger, the PPFD decreases by approximately 75%. Thus the hanging height is a control of the intensity with large steps. Basic lightingreference
IPM (Integrated Pest Management) also IPM: IPM (integrated pest management) is a method with layers: you prevent pests, monitor the crop, use biological control and apply treatments for specified pests. IPM does not use a spray at regular intervals. This paper identifies the pests, and the IPM SOP is the procedure for decisions. IPM SOPreference
ISO 14644: ISO 14644 is the international standard that gives classes of cleanrooms. A class is the maximum permitted number of airborne particles in each cubic meter. GMP hash labreference

J

JSON / data file: A JSON file (data file) is a list of facts that a person can read (room names, sizes and positions). The code reads it to make the model. 3D facility modelprecision

K

KCl storage solution: KCl storage solution is a solution of potassium chloride that keeps the tip of a pH probe wet. If you keep the probe dry or in water without KCl, the probe has permanent damage. pH controlreference
Kelvin (K) / color temperature: The color temperature, in kelvin (K), is a value that shows the mixture of colors of a white LED. A higher value (4000 to 6500 K) gives more blue and is for the vegetative stage. A lower value (3000 to 3500 K) gives more red and is for the flowering stage. Basic lightingreference
Killer item: A killer item is a check that is easy to ignore and dangerous if you do not do it. For example, it can be the dehumidification at lights-off or a dosing pump with no irrigation timeout. A checklist must make this small number of items mandatory. Checks each dayoperations

L

Larf: Larf is a type of flower that is small, has a low density and is not at maturity. It occurs at the bud sites at the bottom of the plant, in shade. It has a low value, and lollipopping removes it. Defoliation and trainingreference
Latent heat load: The latent heat load is the heat in water vapor, and the dehumidifier removes it when the vapor condenses to liquid. Each liter of water that the canopy transpires becomes latent load, and thus a bright room must have a large capacity of dehumidification. The latent load is different from the sensible heat load (dry heat), and at a high light intensity it is frequently the larger of the two. HVAC and dehumidifiersreference
Leading indicator and lagging indicator: A leading indicator is a sign that occurs before the damage, and it tells you about the problem. A lagging indicator is a symptom that shows that the damage occurred. Plant state dashboardprecision
Learned envelope: A learned envelope is the range of values that shows a plant in good condition, for the cultivar, the growth stage and the photoperiod. The system uses it as an alternative to one constant threshold. The closed loopreference
Lever (actuator) also Lever: A lever (actuator) is each control that you can change in the room. The examples are the light intensity, the cooling setpoint, the irrigation shot and the dose of CO2. The paper counts eleven primary groups of levers. The closed loopreference
Life cycle / generation time: The life cycle (generation time) is the time from the egg stage to the egg-laying adult. In warm dry rooms, this time is less than one week for spider mites. As a result, infestations increase very quickly. Pest ID and controlreference
Light saturation: Light saturation is the condition in which a plant cannot use more light, because CO2, water, nutrients, temperature or genetics is the limiting factor. Then more light intensity adds cost and stress, and it does not add yield. Basic lightingreference
Light stress / bleaching: Light stress (bleaching) is damage from too much light intensity. You see the damage as white or yellow bud tips directly below the fixture, leaves with edges that bend up, and less color. The correction is to decrease the intensity of the light or to lift the fixture, and not to apply more feed. Higher light levelsreference
Limiting factor (Liebig's law of the minimum) also Limiting factor: The limiting factor is the one input with the smallest supply compared with the quantity that the plant must have. Only this input sets the growth rate: more of this input increases the growth, and more of a different input gives no change. In a grow room, the weakest support system sets the limit of the yield (usually dehumidification, cooling or CO2), and not the brightest light that the fixtures can make. Grow room systemsreference
Living soil (ROLS) also ROLS: Living soil (ROLS) is an organic soil bed with a large quantity of microbes (recycled organic living soil). The soil has buffering for the pH and supplies nutrients to the plants through its biology. You apply only water, and you can use the soil again and again. Substrates comparedreference
Lockout: Lockout is the condition in which nutrients are chemically not available to the plant. Here, a precipitate causes it when Part A and Part B mix at a high concentration. pH controlreference
Lollipopping: Lollipopping is the procedure in which you remove the small branches, the nodes and the leaves from the bottom third of the plant (approximately the bottom 10 to 18 inches). Thus the energy goes to the top buds, and the plant has the shape of a lollipop. Defoliation and trainingreference
Loupe / scope: A loupe or scope is a magnifier for inspection. A hand loupe of 30x finds spider mites. You must use a magnification of 60 to 100x to find russet mites and broad mites. Pest ID and controlreference
LST (Low-Stress Training) also LST: Low-stress training (LST) is the procedure in which you bend the branches down carefully and attach them in this position. The procedure makes the canopy flat, and you do not cut the plant. The stress is low and there is no recovery time. Defoliation and trainingreference

M

MACO: MACO (Maximum Allowable Carryover) is the residue limit that you calculate. You use it as the acceptance criterion in cleaning validation. GMP hash labreference
Macronutrient: A macronutrient is an element that a plant must absorb in large quantities. The macronutrients are nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S). Nutrient deficienciesreference
Management Review: Management review is the review of the performance and the effectiveness of the quality system, by senior management. The review occurs at regular intervals, a minimum of one time each year. Compliance and traceabilityreference
Manual override: A manual override is a total lockout for each zone. When it is ON, the zone gets no water. The lockout stops automatic irrigation, emergency irrigation and a manual trigger. F2 crop steeringprecision
Mass flow (nutrient uptake) also Mass flow: Mass flow is the primary movement of nutrients in solution to the root surface, with the water that the plant uses when it transpires. Faster transpiration moves more water and more nutrients, and thus the EC of the feed and the light intensity must increase together. If the feed is not sufficient for a bright canopy, the plants have less color. Plant biology 101reference
Master Document Register (REG-QM-001) also REG-QM-001: The Master Document Register (REG-QM-001) is the primary index. It gives a list of all the controlled documents, each with its version at this time, its document owner and its review status. Compliance and traceabilityreference
Median filter: A median filter uses the middle value of the last N readings. It is very good for the removal of a spike in one reading. It does not change a step change that occurs in the plant. Signal and noisereference
Medium (media) also media: A medium is the material that holds a culture and gives nutrients to it. It is a gel of mineral salts, sugar, vitamins and optional hormones. A gelling agent makes the gel solid. Tissue culturetissue culture
Meristem: A meristem is a dome of new cells that divide continuously at the tip of each shoot. No other tissue on the plant is as clean as the meristem, because it is too new to contain most diseases. Tissue culturetissue culture
Micronutrient: A micronutrient is an element that a plant must absorb only in very small quantities. The micronutrients are iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B) and molybdenum (Mo). Nutrient deficienciesreference
Micropropagation: Micropropagation is a method that uses tissue culture to make many copies of one plant. All the copies have the same genes. Tissue culturetissue culture
Mineral salt: Mineral salts are the dry crystals of a nutrient powder, as the supplier sends it. They must dissolve in water before a plant can absorb them. Mix nutrientsreference
Mobile nutrient: A mobile nutrient is a nutrient that the plant can move from the old leaves to the new growth when the supply is not sufficient. The mobile nutrients are N, P, K and Mg. As a result, the deficiency of a mobile nutrient shows first on the old leaves at the bottom of the plant. Nutrient deficienciesreference
Moisture content: Moisture content is the percentage of the weight of the flower that is water. You use it to measure the yield, and not the safety. Harvest, dry, trim, curereference
Mother plant: A mother plant is a stock plant in good condition. You keep it in vegetative growth, and you remove cuttings or explants from it. Mother plantspropagation
Moving average (rolling average) also Moving average: A moving average (rolling average) is the average of the last N readings. You calculate it again when you get each new reading. It decreases random variation, but it adds a small lag. Signal and noisereference
MQS (Minimum Quality Standard) also MQS: The MQS (Minimum Quality Standard) is the quality standard for products of medicinal cannabis in the NZ Misuse of Drugs (Medicinal Cannabis) Regulations 2019. Compliance and traceabilityreference

N

Named condition: A named condition is a short diagnosis that a person can read (for example, 'salt accumulation pattern'). It has a confidence value and an evidence chain. It replaces a large quantity of numbers. Plant state dashboardprecision
Necrosis: Necrosis is the condition in which leaf tissue dies. The tissue becomes brown and dry, and it breaks easily. It occurs frequently at the tips or the edges of the leaves. Nutrient deficienciesreference
Node: A node is the point on a stem where a leaf and a bud attach to the stem. A nodal segment is a short piece of stem that contains one bud. Tissue culturetissue culturepropagation
Noise: Noise is a random change in a measurement that does not show a change in the plant. The examples are a spike in one reading, jitter of high frequency, and transients from doors, the movement of personnel and irrigation events. Signal and noisereference
Nutrient (essential element) also Nutrient: A nutrient (essential element) is one of the chemical elements that a plant must absorb for correct growth. The primary nutrients for cannabis are N, P, K, Ca, Mg and S. The plant must also absorb trace micronutrients such as iron and zinc. Nutrient deficienciesreference
Nutrient antagonism: Nutrient antagonism is the condition in which too much of one element stops the uptake of a different element. For example, too much potassium decreases the uptake of calcium and magnesium. Nutrient deficienciesreference
Nutrient burn: Nutrient burn is the condition in which the tips and the edges of the leaves become brown. It occurs when you apply a solution that is too strong (too much salt). It is one type of toxicity. Nutrient deficienciesreference
Nutrient lockout: Nutrient lockout is the condition in which nutrients are in the substrate, but the roots cannot absorb them because of chemical bonds. It usually occurs because the pH changes to a value that is not in the correct range. The signs are the same as the signs of a deficiency. pH controlreference
Nyquist rule: The Nyquist rule is that the sampling rate must be a minimum of two times the frequency of the fastest cycle that you must find. If the rate is lower, you will read the cycle incorrectly, or the data will show a cycle that does not occur. Signal and noisereference

O

OOS (Out Of Specification) also OOS: An OOS (Out Of Specification) is a test result that is out of the accepted limit. It starts an investigation before the decision to release. Lab testing and COAsreference
Opening: An opening is a gap in a wall, for example a door, a pass-through or a roller door. The data give its position along the wall, its width and its top (head) height. 3D facility modelprecision
Oscillation: In oscillation, a loop makes corrections that are too large, in one direction and then in the other direction. The loop does not become stable. Usually the loop operates too quickly, too strongly, or makes corrections for noise. The closed loopreference

P

P0-P3 phases: The P0-P3 phases are the four irrigation stages of each day. P0 is the morning dryback, P1 is the ramp-up, P2 is the maintenance, and P3 is the stage before lights-off (emergency only). F2 crop steeringprecision
PAR (Photosynthetically Active Radiation) also PAR: PAR (photosynthetically active radiation) is the range of wavelengths from 400 to 700 nm that plants can use for photosynthesis. Lumens, lux and watts do not measure PAR. Thus they do not show the performance of a grow light for plants. Basic lightingreference
Parasitoid wasp: A parasitoid wasp is a very small wasp that is not dangerous to persons, for example Aphidius or Encarsia. The wasp puts eggs in a host pest, and the larva becomes larger and kills the host pest. These wasps are important for aphids and whitefly. IPM SOPreference
Part A (Pro Core) also Part A: Part A (Pro Core) is the primary part of Athena Pro Line. It contains a large quantity of calcium and nitrogen. Always dissolve it in the water first. Mix nutrientsreference
Part B (Pro Grow / Pro Bloom) also Part B: Part B (Pro Grow / Pro Bloom) is the second part. It contains sulfates and phosphates. Add it only after Part A dissolves fully and mixes equally in the water. Mix nutrientsreference
Pause point: A pause point is a time that has a name, at which you do a short checklist, for example lights-on, the first irrigation or pre-dark. A pause point replaces one long sheet that you do at random times. Checks each dayoperations
PCBU: PCBU is the person conducting a business or undertaking. It is the term that the Health and Safety at Work Act 2015 of NZ uses for the employer, who has the legal duty. PPE and biosecurityoperations
Peat: Peat is bog moss that is not fully decomposed. It has a high air-filled porosity, it is acid, and it has a high CEC. Peat is the primary component of most soil mixtures in bags. Substrates comparedreference
Pencil-whipping: Pencil-whipping is the record of a check as done when the person did not do the check. It is the usual result when a check is too slow, when no person has the task, or when no person uses the result. It is not only because a person is not careful. Checks each dayoperations
Permittivity (dielectric constant) also Permittivity: Permittivity (dielectric constant) shows how strong the effect of an electric field is on a material. The value is very high for water (approximately 80), approximately 3 to 5 for dry substrate, and approximately 1 for air. Thus a capacitance sensor can calculate the water content from this difference. Root-zone condition · TEROS-12reference
Permittivity (dielectric) also dielectric: Permittivity is a property of a material that shows how strong the effect of an electric field is on the material. Water has a very high value of permittivity. Thus a moisture probe measures the permittivity and changes it to the water content. Root-zone condition · TEROS-12sensors
PGR (plant growth regulator) also PGR: A PGR (plant growth regulator) is a plant hormone that you add to the medium to control growth. Cytokinins increase the growth of shoots. Auxins increase the growth of roots. Tissue culturetissue culture
pH: pH is a value on a scale of 0 to 14. It shows how acid or alkaline the water is. You usually adjust a nutrient solution to a pH of approximately 5.8 to 6.2. pH controlreference
pH Down / pH Up: The pH Down solution is an acid, usually phosphoric acid. The pH Up solution is alkaline, usually potassium hydroxide. You use them to adjust the pH. pH controlreference
pH lockout: A pH lockout is a condition in which a nutrient is in the root zone, but the plant cannot absorb it. It occurs because the pH of the root zone is not in the range in which that nutrient stays in solution. pH controlreference
pH/EC gate: The pH/EC gate is a safety check. It stops irrigation when the pH or the EC of the source tank is out of the limits that you set (default pH 5.8-6.2). It also sends an alert to your mobile device, with the alternative 'Irrigate Anyway'. F2 crop steeringprecision
Phase (P0-P3) also Phase: The phase of a row is its position in the cycle of each day. P0 is the morning dryback, P1 is the ramp-up, P2 is the maintenance, and P3 is the time before lights-off and the night. F2 crop steeringprecision
Photoinhibition: Photoinhibition is the condition in which a leaf absorbs more light energy than it can use. As a result, photosynthesis decreases and damage to the leaf occurs. Light acclimationreference
Photoperiod: The photoperiod is the number of hours of light and the number of hours of darkness in each day. You write it as hours of light/hours of darkness. For example, 18/6 is for vegetative growth, and 12/12 causes flowering to start and to continue. Basic lightingreference
Photoperiod plant: A photoperiod plant starts flowering only when the hours of light in each day decrease to approximately 12. Regular seeds and feminized seeds give photoperiod plants. Seeds and germinationreference
Phytochrome: Phytochrome is a pigment in a plant that senses red light and far-red light. It changes between the active condition (Pfr, 'it is day') and the condition that is not active (Pr). It measures the length of the continuous period of darkness and starts the flowering signal. Basic lightingreference
PIC/S PE009: PIC/S PE009 is the Guide to GMP for Medicinal Products of the Pharmaceutical Inspection Co-operation Scheme. It is the reference standard, and the manual has a structure that agrees with it. Compliance and traceabilityreference
Pistil: A pistil is a thin hair that extends from a bud site. It is white when it is new, and it becomes orange or brown during ripening. It is an approximate sign of the time to harvest, and it is not accurate. Flower week by weekreference
Plant state: The plant state is the condition of the plant that the system calculates (for example, on-track, stress, or steering generative). The system uses many signals together, and not one instrument. Plant state dashboardreference
Pore-water EC: Pore-water EC is the salt strength of the water that touches the roots (not the bulk EC). It is the EC that the plant gets. Root-zone condition · TEROS-12sensorscrop steering
Post-harvest: Post-harvest is all the tasks that you do after you cut the plant. The tasks include drying, trimming, curing and storage. Harvest, dry, trim, curereference
PPE / PPPE: PPE is personal protective equipment, and PPPE is plant and personal protective equipment. In a grow room, the same gown, gloves and protective covers give the crop protection against the person, and give the person protection against risks. PPE and biosecurityoperationshealth
PPF (Photosynthetic Photon Flux) also PPF: PPF (photosynthetic photon flux) is the total number of PAR photons that a fixture gives in each second (umol/s). It does not show where the photons go. To get the efficacy, divide the PPF by the power of the fixture in watts. Basic lightingreference
PPFD: PPFD is photosynthetic photon flux density. It is the quantity of light on the canopy that the plant can use, in µmol/m²/s. Basic lightingenvironmentlight
PPFD (Photosynthetic Photon Flux Density) also PPFD: PPFD (photosynthetic photon flux density) is the number of photons in the PAR range that one square meter receives in each second. You measure it in micromoles for each square meter for each second (umol/m2/s). It shows how bright the light is at the canopy, and you read it with a quantum meter or PAR meter. Basic lightingreference
PPFD / DLI: PPFD is the intensity of light at one time. DLI is the total quantity of light that the plants receive in one day. The system monitors the DLI up to this time, and not only the PPFD at one time. Basic lightingprecision
PPFD map / PAR map: A PPFD map (PAR map) is a grid from the manufacturer that shows the PPFD across the area below the fixture for specified hanging heights. Use the grid as a start point. Then measure the PPFD with your meter at the canopy height, to make sure that the grid is correct. Basic lightingreference
PPM (parts per million) also PPM: PPM (parts per million) is a unit for the concentration of nutrients in water, and the PPM value changes with the EC value. Different scales change the EC value to a PPM value. Thus the EC value is the same for all meters, and the PPM value is not. Mix nutrientsreference
PPM / TDS: PPM (parts per million), or TDS (total dissolved solids), is the total weight of all the materials in solution in water. PPM meters change the EC value to a PPM value with a 500 scale or a 700 scale. Thus two different meters can give different readings. Water qualityreference
Pre-buffering: Pre-buffering is the procedure in which you soak coco that you cleaned with water in a solution of calcium and magnesium. Thus the exchange sites of the coco do not remove Ca and Mg from your feed. Substrates comparedreference
Precipitate: A precipitate is a solid that comes out of a solution. It occurs when ions that are not compatible, for example calcium with sulfate or phosphate, mix at a high concentration. Mix nutrientsreference
Pressure cascade: A pressure cascade is a sequence of air pressures that you set. A clean room has a higher pressure than the next room that is less clean. Thus air always flows from the clean room to the room that is less clean, and contamination cannot move to the product. GMP hash labreference
Preventative and curative: A preventative agent is an agent that you put in the crop before pests come. It stays in the crop on an alternative food. A curative agent is an agent that you release to decrease an outbreak that is in progress and that becomes larger. IPM SOPreference
Probe drift: Probe drift is the condition in which the accuracy of a pH probe decreases gradually with time. Replace the probe when the drift is more than approximately 0.2 pH between calibrations. pH controlreference
PTZ camera: A PTZ camera is a pan-tilt-zoom camera. It can turn and zoom to monitor a movement. Here it is for coverage of intrusion on the roof. 3D facility modelprecision
Pythium: Pythium is a water mold and a pathogen that causes root rot. It increases in number quickly in a reservoir where the water is warm (more than 23 °C) and the oxygen content is low. Deep water culturereference

Q

QA / QC (Quality Assurance / Quality Control) also QA / QC: QA (Quality Assurance) sets the quality system, monitors it, and makes release decisions independently of production. QC (Quality Control) does the sampling and the testing. Compliance and traceabilityreference
QA / release: QA (Quality Assurance) is the unit (not production) that makes the decision, with a signature, to release a batch to the market. Compliance and traceabilityreference
QMS / PQS (Quality Management System / Pharmaceutical Quality System) also QMS / PQS: A QMS (Quality Management System) or PQS (Pharmaceutical Quality System) is the group of responsibilities, procedures, operations and resources with which an organization controls quality. The manual uses the two names for the same system. Compliance and traceabilityreference
QRM (Quality Risk Management) also QRM: QRM (Quality Risk Management) is a method for decisions on risk, as in ICH Q9. You use it to find, examine and control risks in the system. You also do a review of the risks and give information about the risks. Compliance and traceabilityreference
Quality Manual: The Quality Manual is the top document of the quality system. It gives general information about the quality system, and it refers to the procedures and records below it. Compliance and traceabilityreference
Quarantine: Quarantine is the procedure in which you keep new plants apart from the primary crop. When you receive the plants, clean them. Hold them for a minimum of 2 weeks and monitor them before you put them with the primary crop. IPM SOPreference
Quarantine / Released / Rejected: Quarantine, Released and Rejected are the three statuses of material. Material can have only one of the three statuses. The status of the material and the status in the system must always agree. Compliance and traceabilityreference

R

Raycasting / picking: Raycasting (picking) is the method to find which 3D object you select with the mouse. The software sends a ray that you cannot see from the cursor into the scene. 3D facility modelprecision
Reactive oxygen species: Reactive oxygen species are molecules that cause damage to the leaf tissue and cause bleaching. The plant makes these molecules when it absorbs light energy that it cannot use. This occurs when there is too much light, or when there is not sufficient CO2 to use the energy. Light acclimationreference
Read-do and do-confirm: Read-do and do-confirm are the two types of checklist. In a read-do checklist, you do each step when you read it, for example for setup or calibration. In a do-confirm checklist, you do the tasks without the checklist, then you stop and make sure that you did all the important items. Checks each dayoperations
Recovery floor: The recovery floor is the lowest water content from which a rockwool block can become wet again, equally, from the dripper. At a value less than the floor (approximately 25 to 30% WC), channeling occurs in the fiber and the inner part of the block stays dry. Coco and crop steeringcrop steering
Register: A register is one controlled document that gives an index of records of one type (for example deviations, CAPAs, documents). It becomes larger only when you add rows. Compliance and traceabilityreference
Regular seed: A regular seed is a seed without treatment. It gives approximately equal quantities of male plants and female plants. Seeds and germinationreference
REI (re-entry interval) also REI: The REI (re-entry interval) is the mandatory time that you must wait after a spray before a person can safely go into the room again. A label on the door shows the REI. IPM SOPreference
Relative humidity (RH) also RH: Relative humidity (RH) is the quantity of water vapor that the air contains, as a percentage from 0 to 100%. You keep the dry room at 60% RH. Temperature, humidity and VPDreference
Render: To render is to show the 3D scene as an image on the screen. The software does this many times each second. Thus you can control the scene. 3D facility modelprecision
Representativeness fault: A representativeness fault occurs when the probe works correctly, but its local volume of 1010 mL is not typical of the zone (channeling, air gap, moved probe). The reading is correct for the local volume, but it gives incorrect information about the zone. Root-zone condition · TEROS-12reference
Residual solvent: Residual solvent is the remaining solvent (for example butane and ethanol) in a completed extract. It is a primary safety test, with specified maximum limits in ppm. Lab testing and COAsreference
Resolution and accuracy: Resolution is the smallest change that a sensor can show (0.001 m3/m3 here). Accuracy is how close the value is to the correct value (+/-0.03 with the general equation, +/-0.01-0.02 after calibration). The two are not the same. Root-zone condition · TEROS-12reference
Reverse osmosis (RO) also RO: Reverse osmosis (RO) is filtration in which you push water through a semipermeable membrane. The membrane removes most of the minerals in solution, and the water has almost no PPM (usually 0 to 10 ppm TDS). Water qualityreference
RH: RH is relative humidity. It is the percentage of moisture that the air contains compared with the maximum quantity that the air can contain at that temperature. Temperature, humidity and VPDreference
Ripening: Ripening is the last phase before harvest. In this phase, the pistils darken, the trichomes come to maturity, and the plant moves the nutrients that it keeps into the buds. Ripening and harvestreference
Rockwool (stonewool) also Rockwool: Rockwool (stone wool) is an inert medium of fiber from molten rock. It drains freely, it holds a large quantity of water, and it has almost no buffering. It is alkaline until you soak it. Rockwool and crop steeringreference
Rockwool cube: A rockwool cube is a plug of mineral fiber that holds water and air. A cutting makes roots in it. A peat plug has the same function. Rockwool and crop steeringreference
Root zone: The root zone is the wet substrate directly around the roots. The uptake of nutrients and water occurs there. Root-zone condition · TEROS-12reference
Rooting hormone / IBA: A rooting hormone is a gel or liquid that contains indole-3-butyric acid (IBA), which is a synthetic auxin. Auxin is a plant hormone for roots. You apply the hormone to a stem after you cut the stem, to cause the stem to make roots. Cloningreference
RP (Responsible Person) also RP: An RP (Responsible Person) is the person who has the legal responsibility for the tasks in the regulations. The RP monitors these tasks, gives approval to release a batch, gives approval for recalls, and is the person that the regulator contacts. Compliance and traceabilityreference
Runoff: Runoff is the nutrient water that is more than the pot can hold. It flows out of the bottom of the pot during or after irrigation. Irrigation manualprecision
Runoff / drain: Runoff (drain) is the water that flows out of the bottom of the pot. Irrigation manualprecision

S

Sachet / release box: A sachet or release box is a container, such as a pouch, that you hang on the plant. It releases predator insects onto the plant. It keeps the carrier material out of the irrigation system. IPM SOPreference
Safe headroom: Safe headroom is a lower-confidence-bound estimate of the quantity of water that you can add before the pot is full. It is the only headroom number that gives approval for a shot. Root-zone condition · TEROS-12reference
Sampling cadence: Sampling cadence is how frequently you record a measurement. It must agree with the biology. It must be sufficiently fast to find the changes in the plant, and sufficiently slow to prevent a record of noise that has no value. Signal and noisereference
Scene: The scene is all the objects in the 3D model: slabs, walls, benches, lights and cameras. The model holds them together in one structure. 3D facility modelprecision
Schema: The schema is the agreed structure of the data file. Here it has only four types of record: rooms, walls, equipment and devices. 3D facility modelprecision
Scouting: Scouting is a regular visual inspection of the plants and the traps. You do the inspection to find pests, damage or disease when they first occur. IPM SOPreference
SDI-12: SDI-12 is the digital serial protocol that the TEROS-12 uses to send the VWC, EC and temperature. A value that does not change, that is NaN, or that is at a limit of its range is a hardware fault and not data. Root-zone condition · TEROS-12reference
Seed coat: The seed coat is the hard outer shell of the seed. It gives protection to the embryo until the conditions are correct for the seed to germinate. Seeds and germinationreference
Sensible heat load: The sensible heat load is the dry heat that a grow room must remove, and it comes almost fully from the lights. Nearly all the power of the fixtures becomes heat, and this heat increases the air temperature and is the task of the air conditioner. As an estimate, the watts of light that go into the room are equal to the watts of dry heat that you must remove. HVAC and dehumidifiersreference
Sensor fusion: Sensor fusion is a method to use the signals of some sensors together. Each signal has errors. The method makes one better estimate of the condition, and it gives a confidence value that shows how accurate the estimate is. Irrigation control · VRWEsensorscontrol
Setpoint: A setpoint is the specified number that you give to the equipment. The equipment tries to get this number (for example, 24C for the temperature of the room). The closed loopreference
Setpoint and target: A setpoint is the specified value that a controller tries to keep at this time. A target is the wider result that you want to get for a period of days. The closed loopcontrol
Shade avoidance response: The shade avoidance response is a condition of plants that are too close to each other. The plants use energy to make the weak inner branches longer in the direction of the light. They do not use this energy to make flower of good quality. Defoliation and trainingreference
Shared-drain (sump) problem: The shared-drain puzzle (sump puzzle) occurs when the water from some rooms, from the AC and from the dehumidifier goes into one bucket. Thus you cannot know which source caused a flush. Irrigation control · VRWEprecision
Shot: A shot is one small irrigation event. The size of a shot is a percentage of the water capacity of the pot (for example, a 5% shot). F2 crop steeringprecision
Signal: A signal is a change in the plant or in the root zone that is important for your control. A signal can be a trend that continues, a step change that has a known cause, or a rhythm that occurs each day. Signal and noisereference
Signal and noise: A signal is a change that occurs in the plant or in the root zone. Noise is a small random change from the sensor or from the environment, and it does not show a change in the plant. Good control uses the signal and ignores the noise. Signal and noisecontrolsensors
Signal-to-noise ratio (SNR) also SNR: The signal-to-noise ratio (SNR) is the strength of the signal compared with the strength of all other changes in the data. When the SNR is high, the data are stable and easy to read. When the SNR is low, the data have many changes, and the control adjusts for each change. Signal and noisereference
Sodium (Na) also Na: Sodium (Na) is a salt that is not a nutrient. Well water or coastal water can have a high quantity of sodium. A high quantity of sodium decreases the uptake of nutrients, and thus it is important to select RO. Water qualityreference
Solenoid valve: A solenoid valve is an electrically operated valve. It opens or closes the flow of water when the relay board operates it. Irrigation manualprecision
SOP (standard operating procedure) also SOP: An SOP (standard operating procedure) is a written instruction, with steps, for a task. It lets all personnel do the task with the same correct steps each time. Compliance and traceabilityquality
Source and sink: A source is a leaf with sufficient light that makes more sugar than it uses. A sink is a flower, a root or a leaf in shade that uses more sugar than it makes. When you open the canopy, the sinks that are in shade become sources again. Defoliation and trainingreference
Special-cause variation: Special-cause variation is a change that has a cause that you can find. Something in the operation changes, and the variation is out of the control limits. You must do an investigation. Signal and noisereference
Specific yield (S) also S: Specific yield (S) is the change in VWC for each mL of water that you supply (formula dVWC/delivered_mL). When S becomes almost zero, it is a possible sign that the pot is full, but it is only a possible sign. Root-zone condition · TEROS-12reference
Spectrum: The spectrum is the mixture of the colors of light (wavelengths) that a fixture gives. Blue (400 to 500 nm) gives compact growth. Red (600 to 700 nm) causes flowering and is the range with the highest efficiency for photosynthesis. Basic lightingreference
Spreading: Spreading is the procedure in which you pull the branches away from the primary stalk and put them in the openings of the trellis. Thus light and air go to the middle, and the branches fill the canopy equally. Defoliation and trainingreference
Statistical process control (SPC) also SPC: Statistical process control (SPC) is a method from manufacturing. It uses the recorded data of the operation to find if a change is only usual noise, or a signal for a correction. Signal and noisereference
Stem-snap test: The stem-snap test is a test in which you bend a stem to find if the plant is dry. If the stem breaks and does not fold, the plant is almost sufficiently dry. Harvest, dry, trim, curereference
Sticky trap: A sticky trap is a sheet with a tacky surface, usually yellow or a different color. It catches pests in the air. Thus it gives an indication of pests in the first stage, and you can monitor the number of pests. IPM SOPreference
Stippling: Stippling is a group of small points with less color on the leaves. It occurs when pests make holes in the cells one by one and absorb the sap. It is a usual sign of spider mites and thrips. Pest ID and controlreference
Stretch: Stretch is the fast vertical growth in the first 2 to 3 weeks of flowering. In this time, the plant can become almost two times higher. Then the plant makes buds. Flower week by weekreference
Subculture: Subculture is the task to move the tissue of a culture to new medium. You do the task again at intervals of a small number of weeks. Thus the cultures do not die and continue to increase in number. Tissue culturetissue culture
Substrate: A substrate is the material in which the roots stay. The examples are coco coir, rockwool, peat and soil. Substrates comparedcultivation
Substrate (growing medium) also Substrate: A substrate (growing medium) is the material in which the roots of a plant extend. It holds the plant in position, and it contains water, air and nutrients in solution. Substrates comparedreference
Substrate (medium) also medium: A substrate (medium) is the material in which the roots extend. It can be coco coir, rockwool, water (hydroponics) or soil. The buffering of the pH in the root zone is different for each type of substrate. Substrates comparedreference
Substrate EC: The substrate EC is the strength of the salt in the water in the substrate, where the roots are. Use this reading for the control, and not the EC of the dripper or of the drain. Root-zone condition · TEROS-12crop steeringprecision
Substrate probe: A substrate probe is a sensor in the medium (here GroundWork). It sends the VWC and the EC for a zone. Root-zone condition · TEROS-12precision
Substrate-specific calibration: Substrate-specific calibration is the replacement of the general equation of the probe with an equation that you calculate for your media. The accuracy of the VWC becomes better, from +/-0.03 to +/-0.01-0.02 m3/m3. It is mandatory for accurate steering. Root-zone condition · TEROS-12reference
Sugar leaves: Sugar leaves are small leaves around the bud with trichomes on them. You cut them from the bud with scissors during trimming. Harvest, dry, trim, curereference
System enabled and Auto irrigation: System enabled is the primary arm/kill switch. When it is OFF, no shot occurs. Auto irrigation only stops the automatic shots, and you can apply manual shots. F2 crop steeringprecision

T

Tampering: Tampering is an adjustment of the operation for common-cause variation, as if this variation is special-cause variation. Deming showed that tampering increases the variation of the operation. Signal and noisereference
Tank mix: A tank mix is a mixture of two or more products in one spray tank. Mix only the products that the label lets you put together, and add them in the sequence on the label. IPM SOPreference
Taproot (radicle) also Taproot: The taproot (radicle) is the first white root that extends from a seed. It becomes longer in the down direction, to hold the plant in position and to find water. Seeds and germinationreference
Target: A target is the result that you want to get (for example, a good transpiration rate). A setpoint is only an indicator of the target. The closed loopreference
Telemetry: Telemetry is the sequence of numbers that your sensors send. The numbers include the temperature, the humidity and the moisture. Plant state dashboardcontrol
Terpenes: Terpenes are oils with an aroma. They give each cultivar its aroma and its flavor. They evaporate if the flower becomes too dry. Cannabinoids and terpenesreference
The claw: The claw is the condition in which the tips of the leaves bend down. It is the usual sign of toxicity of nitrogen (too much feed). Nutrient deficienciesreference
The flip: The flip is the change of the photoperiod from 18/6 to 12/12, to cause flowering. The lights are on for a smaller number of hours. Thus the DLI decreases by approximately 28% if the PPFD does not change. Flower week by weekreference
Three.js: Three.js is a code library with no cost that many persons use. It shows 3D scenes that you can control, in a usual web browser. You do not install software. 3D facility modelprecision
Tissue culture (TC) also TC: Tissue culture (TC) is the growth of plant cells, tissues or organs in a vessel without microbes. The plant material stays on a gel with nutrients and not in soil. When you use tissue culture to make many copies of a plant, the name of the method is also micropropagation. Tissue culturetissue culture
Tone mapping: Tone mapping is the step that changes the light intensity of the scene into an image that looks correct. With ACES tone mapping, surfaces of pure white become too bright and show no detail. Thus use a warm off-white. 3D facility modelprecision
Topping: Topping is the procedure in which you cut the top tip of the plant. The plant then does not become higher, and the branches below the tip become two or more new tops. As a result, the plant becomes wider and has more branches. Vegetative stage lengthreference
Total porosity: Total porosity is the fraction of a substrate that is open pore space (air plus water) and not solid material. Substrates comparedreference
Totipotency: Totipotency is a property of plant cells. One plant cell can make a new plant with all its parts, when the cell gets the correct nutrients and hormones. Tissue culturetissue culture
Toxicity: Toxicity is the condition in which the plant has too much of a nutrient, or too much salt in total. The leaves are usually dark green and glossy, with tips that bend down, and the tips have tipburn. The signs are opposite to the signs of a deficiency. Nutrient deficienciesreference
Traceability: Traceability is the property of a product that lets you trace it back and forward through each step and input. It is necessary for recalls and audits. Compliance and traceabilityquality
Transpiration: In transpiration, a plant pulls water up and releases it as vapor through its leaves. Transpiration is a primary cause that connects water, heat and humidity. Temperature, humidity and VPDreference
Transpiration proxy: A transpiration proxy is an estimate of the rate at which the plant transpires. The system calculates it from the VPD, the light and the change in the water content of the substrate. Plant state dashboardprecision
Transpiration stream: The transpiration stream is the continuous flow of water from the roots to the leaves, which the plant releases as vapor through the stomata. The flow moves the nutrients in solution up in the plant, and calcium moves almost fully in this flow. Thus weak transpiration shows as a calcium deficiency when the tank is full. Plant biology 101reference
Transplant: Transplant is the movement of a clone with roots from its cube into a larger container or block. This starts the vegetative stage. Transplantingreference
Trellis / SCROG: A trellis is a horizontal net above the canopy, and the plants become higher through the net. Initially, the net holds the branches apart, and subsequently it holds the heavy buds in position. SCROG is the short name for screen of green. Defoliation and trainingreference
Trichome: A trichome is a very small gland of resin on the buds. It contains most of the THC and the aroma. The color of the trichome (clear, milky white or amber) is the primary signal for the harvest. Ripening and harvestreference
Trichomes: Trichomes are the glands of resin on the bud. They contain THC, terpenes and flavonoids. Ripening and harvestreference
True leaves: True leaves are the usual cannabis leaves, with serrations on the edges. They follow the cotyledons. When the true leaves occur, you start to apply feed. Seeds and germinationreference
Two-part nutrient: A two-part nutrient is a nutrient system with two parts: Part A and Part B. You must add the parts to the water one after the other. If you mix the parts when they are concentrates, a chemical reaction occurs and you cannot use the batch. Mix nutrientsreference
Two-point calibration: A two-point calibration is the calibration of a pH pen with two known buffers, usually pH 7.0 and then pH 4.0. Thus the pH pen gives accurate readings across the range that you use. pH controlreference

U

Uniformity (min-to-average ratio) also Uniformity: Uniformity shows how equally the light goes to all the parts of the canopy. You read the PPFD at nine grid points and divide the lowest value by the average value. A value of more than 0.75 is sufficiently equal. Basic lightingreference
UV-B: UV-B is ultraviolet light of approximately 280 to 315 nm. Some growers add it in the last stage of flowering to try to increase the trichomes and the potency. The data do not agree, and UV-B causes risks to the eyes, the skin and the plants (stress). Basic lightingreference

V

V-model (DQ/IQ/OQ/PQ) also V-model: The V-model is a qualification system for equipment. It connects each design stage to a check that agrees with that stage (Design, Installation, Operational and Performance Qualification). GMP hash labreference
Validation / Qualification: Validation (qualification) is the evidence, in documents, that facilities, equipment, utilities and operations do their specified tasks. GMP hash labreference
Vapor pressure deficit (VPD) also VPD: VPD shows how strongly the air pulls moisture from plants. It is one number that you calculate from the temperature and the humidity. This number changes the rate at which plants transpire. Temperature, humidity and VPDenvironment
Vegetative / Generative mode: The vegetative mode and the generative mode are the two steering modes. They select the dryback targets and the EC targets that the engine uses. The vegetative mode keeps the plant wet and in bulking, and the generative mode causes stress and flowering. F2 crop steeringprecision
Vegetative and generative: The two steering targets are the vegetative target and the generative target. The vegetative target increases the growth of roots and leaves (longer drybacks, lower EC). The generative target increases flowering and fruit (shorter drybacks, higher EC). Coco and crop steeringprecision
Viable / viability: Viability is the condition in which a seed has life and can germinate. The viability decreases when you keep the seeds for a long time or in incorrect conditions. Seeds and germinationreference
Viroid: A viroid is a pathogen with a smaller number of parts than a virus. It is only a short loop of RNA, and it has no protein shell. Mother plantsdisease
Volume of influence: The volume of influence is the part of the media that a probe senses. For the TEROS-12, it is approximately 1010 mL. This volume is large for a dielectric probe, but it is only a local sample of one position. Root-zone condition · TEROS-12reference
Volumetric water content (VWC) also VWC: Volumetric water content (VWC) is the fraction of the total volume of the media that is liquid water, in m3/m3. A value of 0.34 shows that 34% of the volume of the pot is water. It is the primary number for irrigation steering. Root-zone condition · TEROS-12reference
VPD: VPD (vapor pressure deficit) is a value in kPa that you calculate from the temperature and the humidity together. It controls the rate at which a plant transpires. The procedure here uses a VPD of 1.2 to 1.5 kPa. Temperature, humidity and VPDreference
VPD (vapor pressure deficit) also VPD: VPD shows how strongly the air pulls moisture from the plant, and it causes transpiration. You measure it in kPa (for example, 1.4-1.6). The correct value is different for each growth stage. Temperature, humidity and VPDprecision
VRWE (Virtual Root-Zone Water Estimator) also VRWE: VRWE (Virtual Root-Zone Water Estimator) is software that calculates an estimate of the water in the root zone of a plant. It uses some signals together, and then it selects the irrigation. It does not use only one moisture probe. Irrigation control · VRWEprecision
VWC (volumetric water content) also VWC: VWC is the quantity of water in the substrate of the root zone, as a percentage of the volume of the substrate. It is a primary signal for crop steering. Root-zone condition · TEROS-12crop steeringsensors

W

Water activity (Aw) also Aw: Water activity (Aw) shows the quantity of free water that is available to microbes, as a value from 0 to 1. An Aw of <=0.55–0.65 prevents the growth of mold and yeast. Mold riskreference
Water balance: The water balance is the water that you supply (irrigation), minus the water that the plant uses, minus the runoff. You calculate it continuously. It is equal to the estimate of the water in the pot. Irrigation control · VRWEprecision
Water content (WC%) also WC%: Water content (WC%) is the part of the volume of a block or of a pot that is water at this time, as a percentage. In rockwool, the WC is the one value that you control. Root-zone condition · TEROS-12crop steeringprecision
Water-holding capacity: Water-holding capacity is the part of the pore space of a substrate that keeps water after the substrate drains. You give it as a percentage by volume. Substrates comparedreference
Wet trim / dry trim: A wet trim is a trim that you do before drying. A dry trim is a trim that you do after the hang-dry. The source procedure uses a dry trim. Harvest, dry, trim, curereference
Wet weight: Wet weight is the weight of the plants immediately after you cut them and before you dry them. You compare it with the dry weight to get the dry-to-wet ratio. Harvest, dry, trim, curereference
Withholding period: The withholding period is the time that is necessary after a treatment before you can harvest the crop as a product. Thus the residues stay less than the limits. IPM SOPreference

Z

Zone / row: A zone (row) is one of the 3 sections of the room that you control independently. Each section has a pair of probes and a valve. All sections get feed from the same tank. F2 crop steeringprecision
Zone / table: A zone (table) is one of the six grow tables that you control independently. Each table has a valve, a probe and a phase state. F2 crop steeringprecision

#

3D model: A 3D model is an image of the building on a screen. You can turn it, change its size and select parts of it. The software makes it from the floor plan, and it is not a photo or render that does not change. 3D facility modelprecision