Sources & Methodology
Where our numbers come from, what we're still improving, and how to read the estimates.
How the calculator works
The calculator computes yield per cycle from plant density × yield per plant, then multiplies by cycles per year (365 ÷ days to harvest, adjusted for growing method speed). Revenue = yield × your entered price. Costs combine estimated seed/nutrient costs per cycle plus a fixed energy multiplier per m² per year. Water and fertilizer consumption are estimated from the soil baseline then scaled by a saving factor for recirculating hydroponic methods.
Yield, water & fertilizer figures by crop
| Crop | Days to harvest | Yield / plant | Soil water L/m²/day |
Hydro water saving | Soil fertilizer g/m²/cycle |
Hydro fert. saving |
|---|---|---|---|---|---|---|
| Lettuce | 35 (soil) / 31 (hydro) | 0.18 kg | 3.5 | ↓ 72% | 45 g | ↓ 45% |
| Basil | 30 (soil) / 27 (hydro) | 0.12 kg | 4.0 | ↓ 75% | 40 g | ↓ 50% |
| Tomato | 90 (soil) / 90 (dutch) | 4.5 kg | 6.0 | ↓ 67% | 180 g | ↓ 40% |
| Spinach | 40 (soil) / 36 (hydro) | 0.10 kg | 3.0 | ↓ 70% | 35 g | ↓ 48% |
| Strawberry | 90 (soil) / 90 (dutch) | 0.40 kg | 4.5 | ↓ 68% | 90 g | ↓ 42% |
| Cucumber | 60 (soil) / 60 (dutch) | 3.0 kg | 5.5 | ↓ 70% | 150 g | ↓ 40% |
What fertilizers are saved in hydroponic systems More detail coming soon
In soil cultivation, a significant portion of applied fertilizer is lost to leaching, runoff, and fixation in the soil matrix — estimates from the literature range from 30–60% loss depending on irrigation management and soil type. Hydroponic systems in a closed recirculating loop allow near-complete nutrient uptake, with losses limited primarily to plant uptake inefficiency and periodic reservoir changes.
The nutrients primarily saved include nitrogen (N) — the most commonly leached macro-nutrient — followed by phosphorus (P) and potassium (K). Micronutrients like iron, manganese, and zinc are used in precisely dosed chelated form in hydroponic solutions, eliminating the over-application common in soil broadcasting.
Sources backing our numbers
Core reference for hydroponic yield benchmarks, plant densities, and water use comparisons across leafy crops, tomatoes, and cucumbers grown in controlled environments.
https://www.fao.org/3/w2384e/w2384e00.htmProvides quantified water and fertilizer efficiency data comparing NFT lettuce production to field and greenhouse soil production. Core basis for our water-saving percentages.
https://doi.org/10.1016/j.jclepro.2015.01.009Overview of water usage reductions (up to 90% vs soil) in recirculating hydroponic systems, with figures for basil, lettuce, and spinach.
Fertilizer application rates and nutrient recovery efficiency in closed vs open hydroponic systems. Used to derive our fertilizer saving factors for tomato, cucumber, and strawberry.
https://doi.org/10.17660/ActaHortic.1999.481.1Soil fertilizer application rate references for tomato, pepper, cucumber, and leafy greens. Used as soil baseline figures in our fertilizer comparison.
https://edis.ifas.ufl.edu/publication/CV009Industry-standard reference for plant densities, yield per plant, and cycle lengths in NFT, DWC, and Dutch bucket systems. Primary source for our density and yield-per-plant figures.
Used for context on controlled-environment agriculture water efficiency claims; not used directly for quantitative figures.
What we're working on
- Per-nutrient fertilizer breakdowns — N, P, K, Ca, Mg and key micronutrients per crop per system, with soil vs hydro comparison
- Expanded crop library — peppers, herbs (mint, coriander), microgreens, and fruiting crops
- CO₂ footprint estimate — energy source-adjusted carbon per kg of produce
- Regional water pricing — integrate local water cost data so savings translate to €
- Validated local yield data — working with growers in Spain, France, and the UK to cross-check our estimates against real production logs
If you have production data you'd be willing to share, we'd love to hear from you. Get in touch →