Calculator methodology and assumptions

Every planning number on SeedMatch Group comes from one central calculation engine. Each model below is version-controlled and states its purpose, its inputs, the arithmetic it performs, the agronomic and engineering assumptions it relies on, what it cannot tell you, and the institutional sources behind the method. The same inputs return the same outputs on every page and in every RFQ, and each formula can be reproduced by hand.

Planning estimate only. Final crop, variety, greenhouse, irrigation, fertigation, structural, hydraulic, energy and financial decisions must be confirmed by qualified independent professionals, the selected provider and applicable authorities. SeedMatch Group does not guarantee germination, emergence, yield, quality, crop cycle, disease resistance, water consumption, energy savings, market price, revenue or project return.

A machine-readable version of this registry is published at /calculator-methodology.json.

Plant population and spacing

v1.0.0 · planning confidence · reviewed 2026-08-21 by the SeedMatch Group editorial team

Convert a planting geometry into an indicative plant population for an area, so seed, transplant, dripline and yield planning all start from the same number.

Crops: Row-planted field and greenhouse crops with a regular spacing grid.
Production systems: Open field, protected cultivation, substrate rows.
Climate range: Climate-independent — geometry only.

Inputs

Planted area (ha · buyer input) — > 0
Row spacing (m · buyer input) — > 0
In-row plant spacing (m · buyer input) — > 0
Plants per position (count · buyer input) — >= 1 Default 1.

Outputs

Plants per hectare (plants/ha · calculated output)
Total plants (plants · calculated output)
Area per plant (m² · calculated output)

Formula

area per plant (m²) = row spacing (m) × in-row spacing (m) ÷ plants per position
plants per hectare = 10,000 ÷ area per plant
total plants = plants per hectare × planted area (ha)

Agronomic assumptions

A uniform, fully planted grid with no gaps, headlands, roads or service areas deducted.
Spacing is the agronomic decision of the grower or agronomist; the model does not propose a density.

Engineering assumptions

None — the model is pure geometry.

Limitations

Does not account for field shape, headlands, paths, gutters or service corridors.
Does not adjust for expected field establishment; use the seed-rate model for that.

Used on

Greenhouse area and production planner

v1.0.0 · planning confidence · reviewed 2026-08-21 by the SeedMatch Group editorial team

Work backwards from an annual marketable-production target to the net growing area, gross covered area and indicative plant population a project needs.

Crops: Greenhouse vegetable and leafy crops where a marketable yield scenario can be stated with its context.
Production systems: Protected cultivation: soil, substrate, hydroponic gutters, NFT.
Climate range: Any — the yield scenario must be supplied for the specific climate and technology.

Inputs

Annual marketable production target (kg/year · buyer input) — > 0
Marketable yield scenario per cycle (kg/m²/cycle · crop reference) — > 0 — must state crop, variety context, climate, technology, system, period, source and date
Crop cycles per year (cycles/year · buyer input) — > 0
Pack-out percentage (% · buyer input) — 0 < value <= 100
Crop-loss scenario (% · buyer input) — 0 <= value < 100
Support, path, nursery and packing area (% of net growing area · buyer input) — >= 0
Future expansion allowance (% · buyer input) — >= 0 Default 0.

Outputs

Net growing area (m² · calculated output)
Support area (m² · calculated output)
Gross greenhouse area (m² · calculated output)
Marketable production per cycle (kg · calculated output)

Formula

effective marketable yield (kg/m²/cycle) = yield scenario × (1 − crop loss %) × pack-out %
net growing area (m²) = annual target ÷ (effective yield × cycles per year)
support area (m²) = net growing area × support area %
gross area (m²) = (net growing area + support area) × (1 + expansion %)

Agronomic assumptions

No universal yield per m² is applied. The yield scenario is an input that must name its crop, variety context, climate, greenhouse technology, growing system, production period, source and date.
Cycles per year reflect the planned cropping calendar for the site, not a theoretical maximum.

Engineering assumptions

Gross area is a planning envelope, not a structural layout. Bay width, gutter height, module length and orientation come from the supplier's or engineer's layout.

Limitations

Sensitive to the yield, pack-out and loss scenario; a 10% change in any of them moves the required area by roughly the same proportion.
Does not size climate equipment, structure or foundations.

Sources

Good Agricultural Practices for greenhouse vegetable production — Food and Agriculture Organization of the United Nations (FAO), 2013, accessed 2026-08-21 (primary source)

Used on

Crop water requirement and irrigation demand

v1.0.0 · planning confidence · reviewed 2026-08-21 by the SeedMatch Group editorial team

Produce a preliminary net and gross irrigation requirement from reference evapotranspiration, a crop coefficient, the irrigated area and system efficiency.

Crops: Any crop for which a crop coefficient (Kc) is available for the growth stage in question.
Production systems: Open field and protected cultivation (with a greenhouse reduction factor).
Climate range: Any, provided ETo is supplied for the location and period.

Inputs

Reference evapotranspiration (ETo) (mm/day · location derived) — > 0 — label the source and period; no live weather is used
Crop coefficient (Kc) for the growth stage (ratio · crop reference) — > 0
Irrigated area (ha · buyer input) — > 0
Irrigation system efficiency (fraction · buyer input) — 0 < value <= 1
Effective rainfall (mm/day · location derived) — >= 0 Default 0.
Leaching requirement (fraction · buyer input) — 0 <= value < 1 Default 0.
Greenhouse reduction factor (ratio · editorial assumption) — 0 < value <= 1 — enter 1 for open field Default 1.
Peak-to-average design factor (ratio · buyer input) — >= 1 Default 1.3.

Outputs

Crop evapotranspiration (ETc) (mm/day · calculated output)
Net irrigation requirement (mm/day · calculated output)
Gross irrigation requirement (mm/day · calculated output)
Average daily volume (m³/day · calculated output)
Peak daily volume (m³/day · calculated output)
Volume over the operating period (m³ · calculated output)

Formula

ETc (mm/day) = ETo × Kc × greenhouse factor
net requirement (mm/day) = max(0, ETc − effective rainfall)
gross requirement (mm/day) = net requirement ÷ (irrigation efficiency × (1 − leaching fraction))
volume (m³/day) = gross requirement (mm/day) × area (ha) × 10
peak daily volume = average daily volume × peak factor
period volume = average daily volume × operating days

Agronomic assumptions

Kc is stage-specific. A single seasonal Kc understates peak demand and is only acceptable for a first screening.
Effective rainfall is the fraction that reaches the root zone, not total rainfall.

Engineering assumptions

Irrigation efficiency covers distribution uniformity and system losses as one factor; a hydraulic design separates them.
1 mm over 1 ha = 10 m³.

Limitations

No live weather feed is used. ETo must be supplied with its source and period.
Does not replace a hydraulic design, a water balance or a laboratory water analysis.

Sources

FAO Irrigation and Drainage Paper 56 — Crop evapotranspiration (guidelines for computing crop water requirements) — Food and Agriculture Organization of the United Nations (FAO), 1998, accessed 2026-08-21 (primary source)

Used on

Drip, emitter and zone screening

v1.0.0 · screening confidence · reviewed 2026-08-21 by the SeedMatch Group editorial team

Convert a drip layout into emitter counts, zone flow and total system flow so a buyer can state a credible flow requirement in an RFQ.

Crops: Row crops irrigated by dripline.
Production systems: Open-field drip, greenhouse drip, substrate drip.
Climate range: Climate-independent — geometry and hydraulics only.

Inputs

Irrigated area (ha · buyer input) — > 0
Row spacing (m · buyer input) — > 0
Driplines per row (count · buyer input) — >= 1 Default 1.
Emitter spacing (m · buyer input) — > 0
Emitter nominal flow (L/h · supplier confirmed) — > 0
Number of irrigation zones (count · buyer input) — >= 1 Default 1.
Irrigation duration per shift (h · buyer input) — > 0

Outputs

Total dripline length (m · calculated output)
Emitter count (count · calculated output)
Flow if all zones run together (L/h · calculated output)
Flow per zone (m³/h · calculated output)
Water applied per zone shift (m³ · calculated output)
Depth applied per zone shift (mm · calculated output)

Formula

dripline length (m) = area (ha) × 10,000 ÷ row spacing × driplines per row
emitter count = dripline length ÷ emitter spacing
system flow (L/h) = emitter count × emitter flow
zone flow (m³/h) = system flow ÷ zones ÷ 1,000
applied per zone shift (m³) = zone flow × run hours
depth applied (mm) = applied volume (m³) ÷ (zone area in ha × 10)

Agronomic assumptions

Application depth is compared with the crop's net requirement by the buyer or agronomist; the model does not schedule irrigation.

Engineering assumptions

Emitter flow is the manufacturer's nominal flow at its rated pressure. Actual flow varies with pressure, temperature and clogging.
Zones are assumed equal in area; unequal zones must be calculated separately.

Limitations

Does not determine pipe sizes, pressure losses, valve selection, mainline routing or lateral run limits — those require a hydraulic design.
Uniformity is not modelled; a manufacturer's emission uniformity figure is a supplier-confirmed value.

Sources

FAO Irrigation and Drainage Paper 56 — Crop evapotranspiration (guidelines for computing crop water requirements) — Food and Agriculture Organization of the United Nations (FAO), 1998, accessed 2026-08-21 (primary source)

Used on

Pump and hydraulic screening

v1.0.0 · screening confidence · reviewed 2026-08-21 by the SeedMatch Group editorial team

Estimate total dynamic head, hydraulic power and electrical input for a pumping duty so a buyer can request comparable pump proposals.

Crops: Not crop-specific.
Production systems: Any irrigation or water-transfer duty.
Climate range: Climate-independent.

Inputs

Required flow (m³/h · buyer input) — > 0
Static suction head (m · buyer input) — >= 0 Default 0.
Static delivery head (elevation) (m · buyer input) — >= 0
Pipe and fitting friction losses (m · requires professional review) — >= 0
Filtration loss allowance (m · supplier confirmed) — >= 0 Default 0.
Fertigation loss allowance (m · supplier confirmed) — >= 0 Default 0.
Required operating pressure at the emitter (m head · supplier confirmed) — >= 0
Pump efficiency (fraction · supplier confirmed) — 0 < value <= 1
Motor efficiency (fraction · supplier confirmed) — 0 < value <= 1

Outputs

Preliminary total dynamic head (m · calculated output)
Hydraulic power (kW · calculated output)
Pump shaft power (kW · calculated output)
Estimated electrical input (kW · calculated output)

Formula

TDH (m) = static suction + static delivery + friction losses + filtration loss + fertigation loss + operating pressure
hydraulic power (kW) = ρ × g × Q(m³/s) × H(m) ÷ 1,000, with ρ = 1,000 kg/m³ and g = 9.81 m/s²
shaft power (kW) = hydraulic power ÷ pump efficiency
electrical input (kW) = shaft power ÷ motor efficiency

Agronomic assumptions

None.

Engineering assumptions

Clean water at ambient temperature, density 1,000 kg/m³.
Friction losses are an input, not a derived value: they depend on pipe material, diameter, length, fittings and flow.
Duty/standby redundancy, NPSH, cavitation margin, starting method and variable-speed control are engineering decisions outside this model.

Limitations

Does not select a pump model, impeller or motor frame.
Hydraulic power depends on flow, total head, fluid density and gravity; the electrical input additionally depends on pump and motor efficiency, which are supplier-confirmed values.

Sources

FAO Irrigation and Drainage Paper 56 — Crop evapotranspiration (guidelines for computing crop water requirements) — Food and Agriculture Organization of the United Nations (FAO), 1998, accessed 2026-08-21 (primary source)

Used on

/pump-sizing-calculator

Greenhouse ventilation and evaporative cooling screening

v1.0.0 · screening confidence · reviewed 2026-08-21 by the SeedMatch Group editorial team

Convert greenhouse geometry and a target air-exchange rate into an indicative airflow and fan count, and flag where evaporative cooling is limited by humidity.

Crops: Not crop-specific; the target internal condition is a crop decision.
Production systems: Naturally ventilated and mechanically ventilated greenhouses.
Climate range: Any — but evaporative cooling performance depends on the local wet-bulb condition.

Inputs

Greenhouse length (m · buyer input) — > 0
Greenhouse width (m · buyer input) — > 0
Average internal height (m · buyer input) — > 0
Target air changes per hour (1/h · requires professional review) — > 0
Rated fan capacity at design static pressure (m³/h · supplier confirmed) — > 0
Natural vent opening area (m² · buyer input) — >= 0 Default 0.
External design dry-bulb temperature (°C · location derived) — any
External design wet-bulb temperature (°C · location derived) — <= dry bulb
Cooling pad saturation efficiency (fraction · supplier confirmed) — 0 < value <= 1

Outputs

Greenhouse volume (m³ · calculated output)
Floor area (m² · calculated output)
Indicative airflow requirement (m³/h · calculated output)
Indicative fan count at the entered rated capacity (count · calculated output)
Vent area as a share of floor area (% · calculated output)
Theoretical pad outlet temperature (°C · calculated output)
Theoretical temperature drop (K · calculated output)

Formula

volume (m³) = length × width × average height
airflow (m³/h) = volume × air changes per hour
fan count = ceiling(airflow ÷ rated fan capacity at design static pressure)
vent ratio (%) = vent area ÷ floor area × 100
pad outlet (°C) = dry bulb − pad efficiency × (dry bulb − wet bulb)

Agronomic assumptions

The target internal temperature and humidity band belong to the crop plan and must come from an agronomist.

Engineering assumptions

Rated fan capacity must be the manufacturer's figure at the project's design static pressure, not free air.
Air changes per hour is a design parameter set by the climate designer; the model does not propose one.
Evaporative cooling cannot go below the ambient wet-bulb temperature, and the achievable drop shrinks as humidity rises.

Limitations

No internal temperature is guaranteed. Solar load, crop transpiration, screen configuration, elevation, leakage and control strategy all change the result.
Does not size vents, screens, pad area, pumps or controls — that is a climate design.

Sources

Good Agricultural Practices for greenhouse vegetable production — Food and Agriculture Organization of the United Nations (FAO), 2013, accessed 2026-08-21 (primary source)

Used on

/greenhouse-climate-calculator

Greenhouse peak heating load screening

v1.0.0 · screening confidence · reviewed 2026-08-21 by the SeedMatch Group editorial team

Estimate the peak heat loss of a greenhouse envelope at the design outside temperature.

Crops: Not crop-specific; the internal target is a crop decision.
Production systems: Protected cultivation.
Climate range: Heating climates; requires a design outside temperature for the site.

Inputs

Envelope (covered) surface area (m² · buyer input) — > 0
Covering U-value (W/m²·K · supplier confirmed) — > 0
Inside target temperature (°C · requires professional review) — any
Outside design temperature (°C · location derived) — < inside target
Thermal screen reduction (fraction · supplier confirmed) — 0 <= value < 1 Default 0.
Infiltration allowance (fraction · requires professional review) — >= 0 Default 0.
Heating system efficiency (fraction · supplier confirmed) — 0 < value <= 1 Default 1.

Outputs

Transmission heat loss (kW · calculated output)
Peak heating load including infiltration (kW · calculated output)
Required heat input at system efficiency (kW · calculated output)

Formula

ΔT (K) = inside target − outside design temperature
transmission loss (kW) = envelope area × U-value × (1 − screen reduction) × ΔT ÷ 1,000
peak load (kW) = transmission loss × (1 + infiltration allowance)
required input (kW) = peak load ÷ system efficiency

Agronomic assumptions

The inside target temperature comes from the crop plan.

Engineering assumptions

Steady-state envelope loss only. Solar gain, thermal mass, wind exposure, floor and perimeter losses and the control strategy are not modelled.
U-value must be the covering's certified value for the installed configuration.

Limitations

A screening figure for comparing options, not a heating design or an equipment selection.
Annual energy cannot be derived from a peak load without a declared operating profile.

Used on

Seed rate and seed quantity

v1.0.0 · planning confidence · reviewed 2026-08-21 by the SeedMatch Group editorial team

Convert a target plant population into a seed quantity, correcting for germination, purity and expected field establishment.

Crops: Directly sown field and vegetable crops; transplanted crops use the nursery variant with the same correction chain.
Production systems: Open field and protected cultivation.
Climate range: Climate-independent — establishment expectation carries the site effect.

Inputs

Target plant population (plants/ha · buyer input) — > 0
Germination percentage on the lot certificate (% · supplier confirmed) — 0 < value <= 100
Analytical purity percentage (% · supplier confirmed) — 0 < value <= 100 Default 100.
Expected field establishment (% · buyer input) — 0 < value <= 100
Thousand-seed weight (g · supplier confirmed) — > 0 — or supply seeds per kg instead
Planted area (ha · buyer input) — > 0
Safety allowance (% · buyer input) — >= 0 Default 0.
Bag size (kg · supplier confirmed) — > 0

Outputs

Seeds required per hectare (seeds/ha · calculated output)
Seed rate (kg/ha · calculated output)
Total seed quantity (kg · calculated output)
Bags at the entered bag size (count · calculated output)
Resulting plant population (plants/ha · calculated output)

Formula

seeds per hectare = target population ÷ (germination % × purity % × establishment %) × (1 + safety allowance)
seeds per kg = 1,000,000 ÷ thousand-seed weight (g)
seed rate (kg/ha) = seeds per hectare ÷ seeds per kg
total seed (kg) = seed rate × area
bags = ceiling(total seed ÷ bag size)

Agronomic assumptions

Germination and purity are the figures on the lot's own analysis certificate, not catalogue values.
Field establishment is a site expectation set by the grower or agronomist; it is not a property of the seed.

Engineering assumptions

Sowing equipment calibration and singulation accuracy are outside the model.

Limitations

Does not predict emergence, yield or crop performance, and is not a variety recommendation.
Coated, pelleted and primed seed change thousand-seed weight — use the figure for the lot actually supplied.

Sources

International Rules for Seed Testing — International Seed Testing Association (ISTA), accessed 2026-08-21 (primary source)

Used on

Project CAPEX, OPEX and unit cost

v1.0.0 · planning confidence · reviewed 2026-08-21 by the SeedMatch Group editorial team

Separate equipment-only cost from installed cost and total project cost, and express both CAPEX and OPEX per unit of area and of marketable production.

Crops: Not crop-specific.
Production systems: Any commercial agricultural project.
Climate range: Not applicable.

Inputs

Equipment and materials cost (currency · supplier confirmed) — >= 0
Installation and commissioning (currency · supplier confirmed) — >= 0
Freight, insurance and duties (currency · buyer input) — >= 0
Site preparation, drainage and civil works (currency · buyer input) — >= 0
Professional services and permits (currency · buyer input) — >= 0
Other project costs (land, support buildings, utilities) (currency · buyer input) — >= 0 Default 0.
Contingency (% · buyer input) — >= 0
Working capital (currency · buyer input) — >= 0 Default 0.
Annual operating cost (currency/year · buyer input) — >= 0
Gross project area (m² · buyer input) — > 0
Annual marketable production (kg/year · calculated output) — > 0

Outputs

Equipment-only CAPEX (currency · calculated output)
Installed CAPEX (currency · calculated output)
Total project CAPEX including contingency and working capital (currency · calculated output)
CAPEX per m² (currency/m² · calculated output)
CAPEX per hectare (currency/ha · calculated output)
Operating cost per marketable kg (currency/kg · calculated output)

Formula

equipment-only CAPEX = equipment and materials
installed CAPEX = equipment-only + installation + freight and duties
base project cost = installed CAPEX + site preparation + professional services + other project costs
total project CAPEX = base project cost × (1 + contingency %) + working capital
CAPEX per m² = total project CAPEX ÷ gross area; CAPEX per hectare = CAPEX per m² × 10,000
operating cost per kg = annual OPEX ÷ annual marketable production

Agronomic assumptions

Annual marketable production comes from the greenhouse-area model or the buyer's own plan.

Engineering assumptions

Cost inputs must be quotations or the buyer's own budget figures. The model publishes no price benchmarks.

Limitations

Equipment price is never presented as total project cost — the three levels are reported separately.
Excludes financing cost, tax effects and currency movement unless the buyer includes them in the inputs.

Used on

ROI, payback, NPV and IRR scenarios

v1.0.0 · comparative confidence · reviewed 2026-08-21 by the SeedMatch Group editorial team

Express a project's cash-flow arithmetic under conservative, base and upside scenarios, including break-even yield and price.

Crops: Not crop-specific.
Production systems: Any commercial agricultural project.
Climate range: Not applicable.

Inputs

Total project CAPEX (currency · calculated output) — > 0
Annual marketable production (kg/year · buyer input) — > 0
Selling price entered by the buyer (currency/kg · buyer input) — > 0 — no market price is supplied by SeedMatch
Annual operating cost (currency/year · buyer input) — >= 0
Project life (years · buyer input) — >= 1
Discount rate (fraction · buyer input) — >= 0
Ramp-up factors by year (fraction per year · buyer input) — each 0 <= value <= 1
Residual value at end of life (currency · buyer input) — >= 0 Default 0.

Outputs

Revenue at full production (currency/year · calculated output)
Operating margin at full production (currency/year · calculated output)
Simple payback (years · calculated output)
Discounted payback (years · calculated output)
Net present value (currency · calculated output)
Internal rate of return (fraction · calculated output)
Break-even price (currency/kg · calculated output)
Break-even volume (kg/year · calculated output)

Formula

year n production = annual marketable production × ramp-up factor for year n
year n cash flow = year n production × price − annual OPEX
NPV = −CAPEX + Σ (year n cash flow ÷ (1 + discount rate)^n) + residual value ÷ (1 + discount rate)^life
IRR = the discount rate at which NPV = 0, found by bisection; reported only when a sign change exists
simple payback = the first year in which cumulative undiscounted cash flow turns positive, interpolated within the year
break-even price = annual OPEX ÷ annual marketable production
break-even volume = annual OPEX ÷ price

Agronomic assumptions

Yield and pack-out scenarios come from the greenhouse-area model or the buyer's own plan.

Engineering assumptions

Replacement of covering and equipment is included only where the buyer enters it in OPEX or as a separate cash flow.

Limitations

Arithmetic only. It does not state whether a project is viable, profitable, bankable or fundable — that is a lender's and an investor's assessment.
No market price is supplied. Revenue is only as reliable as the price the buyer enters.
IRR is undefined when cash flows never change sign; the model returns null rather than a misleading number.

Sources

IFC Agribusiness and Forestry — investment and advisory approach — International Finance Corporation (IFC), accessed 2026-08-21 (primary source)

Used on

Solar and battery backup screening

v1.0.0 · screening confidence · reviewed 2026-08-21 by the SeedMatch Group editorial team

Give an indicative PV array and battery capacity for a stated load, and separate the critical load from the total load.

Crops: Not crop-specific.
Production systems: Irrigation pumping, climate equipment, packhouse and support loads.
Climate range: Requires a solar resource figure for the site.

Inputs

Average daily electrical load (kWh/day · buyer input) — > 0
Peak sun hours (h/day · location derived) — > 0 — state the source and period
System performance ratio (fraction · editorial assumption) — 0 < value <= 1 Default 0.75.
Critical load to be covered (kWh/day · buyer input) — >= 0
Autonomy requirement (days · buyer input) — >= 0
Usable depth of discharge (fraction · supplier confirmed) — 0 < value <= 1
Round-trip efficiency (fraction · supplier confirmed) — 0 < value <= 1 Default 0.9.

Outputs

Indicative PV capacity (kWp · calculated output)
Indicative annual PV generation (kWh/year · calculated output)
Indicative battery capacity (kWh · calculated output)
Share of daily load classed as critical (% · calculated output)

Formula

PV capacity (kWp) = daily load ÷ (peak sun hours × performance ratio)
annual generation (kWh) = PV capacity × peak sun hours × performance ratio × 365
battery capacity (kWh) = critical load × autonomy days ÷ (depth of discharge × round-trip efficiency)
critical share (%) = critical load ÷ daily load × 100

Agronomic assumptions

None.

Engineering assumptions

Performance ratio bundles soiling, temperature, wiring, inverter and availability losses into one factor.
Seasonal variation, the hourly load profile, night-time pumping and inverter sizing are not modelled.
Battery degradation over life is not applied; the supplier's warranty terms govern.

Limitations

No claim of energy independence or continuous irrigation. Night-time operation, seasonal resource, storage and backup generation must be checked in a design.
Savings depend on the tariff the buyer enters, which is a location-derived value that must be dated.

Sources

Renewable energy for agri-food systems — International Renewable Energy Agency (IRENA) / FAO, 2021, accessed 2026-08-21 (primary source)

Used on

Fertigation stock solution and injection

v1.0.0 · planning confidence · reviewed 2026-08-21 by the SeedMatch Group editorial team

Convert a nutrient target set by the buyer or their agronomist into a product quantity, a stock-solution volume and an injection requirement.

Crops: Any fertigated crop — the nutrient target itself is always an agronomic input.
Production systems: Drip fertigation, hydroponic recirculation, substrate systems.
Climate range: Not applicable.

Inputs

Target nutrient concentration entered by the buyer or agronomist (mg/L (ppm) · requires professional review) — > 0
Irrigation volume to be dosed (m³ · calculated output) — > 0
Nutrient content of the fertilizer (% w/w · supplier confirmed) — 0 < value <= 100
Nutrient already present in the source water (mg/L · requires professional review) — >= 0 — from a laboratory analysis Default 0.
Stock concentration factor (× · buyer input) — >= 1
Stock tank volume (L · buyer input) — > 0

Outputs

Nutrient to be supplied by fertilizer (mg/L · calculated output)
Fertilizer product required (kg · calculated output)
Stock solution volume required (L · calculated output)
Injection ratio (1:x · calculated output)
Stock tank batches (count · calculated output)

Formula

net concentration (mg/L) = max(0, target − concentration already in the source water)
nutrient mass (kg) = net concentration (mg/L) × irrigation volume (m³) ÷ 1,000
product mass (kg) = nutrient mass ÷ nutrient content %
stock solution volume (L) = irrigation volume (m³) × 1,000 ÷ stock concentration factor
injection ratio = 1 : stock concentration factor
batches = ceiling(stock volume ÷ tank volume)

Agronomic assumptions

The nutrient target is never generated by SeedMatch. It is entered by the buyer or their agronomist for the crop, stage, substrate and water analysis in question.

Engineering assumptions

Assumes the fertilizer fully dissolves at the stock concentration and temperature in use; solubility limits are product-specific.
Injector accuracy, pressure and calibration are supplier-confirmed values.

Limitations

Not a fertilizer programme and not a nutrient recommendation.
Does not check chemical compatibility automatically. Keep calcium sources separate from sulphates and phosphates in concentrated stock, handle acids according to local safety requirements, and have the recipe reviewed before mixing.
Source-water nutrients require a current laboratory analysis; without one, the net concentration cannot be trusted.

Sources

FAO Irrigation and Drainage Paper 29 — Water quality for agriculture — Food and Agriculture Organization of the United Nations (FAO), 1985 (rev. 1), accessed 2026-08-21 (primary source)