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Polyhouse tomato Water Requirement Calculator

Work out the seasonal and per-irrigation water requirement of polyhouse tomato (FAO-56 ETc = ET₀ × Kc, peak Kc 1.1) for your field, climate, soil and irrigation method.

4937 m³
Seasonal water for 1 acre of polyhouse tomato
29.7 m³/day
Peak daily need
5 days
Irrigate every
Season length200 days
Net seasonal ET (crop)1098 mm
Gross seasonal (after drip / micro losses)1220 mm
Peak crop ET (ETc = ET₀ × Kc)6.6 mm/day (Kc 1.1)
Net depth per irrigation33 mm
Volume per irrigation135 m³

Inside a polyhouse, evaporative demand (ET0) is lower, so water need drops — but the long-duration indeterminate crop runs for months on daily drip fertigation. Match doses to the lower indoor ET0, not field values.

Sources: FAO-56 Kc for tomato (Kc mid 1.1); protected-cultivation ET0 reduction (~25–30%); Method: ETc = ET₀ × Kc (FAO-56); efficiency: drip 90%, sprinkler 75%, pivot 80%, surface 60%

Indicative planning figures based on published research averages. Local soil tests, varieties and weather change actual requirements — confirm with your agronomist or extension officer.

Disclaimer: This tool is for general informational and estimation purposes only and is not professional financial, tax, accounting or legal advice. All figures are estimates — verify with a qualified professional before making decisions. Read the full disclaimer.

Farmers and irrigation planners use the free Polyhouse tomato Water Requirement Calculator to turn the FAO-56 crop coefficients for polyhouse tomato into a real seasonal water volume and an irrigation interval for their own field — no agronomy tables, works offline.

About Polyhouse tomato Water Requirement Calculator

Protected (polyhouse) tomato uses ~25–30% less water than open field for the same crop, delivered precisely by drip fertigation. This calculator uses the FAO-56 method — crop evapotranspiration ETc = ET₀ × Kc — with polyhouse tomato's own crop coefficients (Kc 0.6 initial, 1.1 mid-season, 0.8 late) across a 200-day season. Pick your climate band (which sets reference ET₀), irrigation method (drip, sprinkler, pivot or surface — each with its own efficiency) and soil texture, and it returns the seasonal water need in cubic metres, the peak daily demand, the net depth per irrigation and how many days to wait between irrigations.

How to use Polyhouse tomato Water Requirement Calculator

  1. 1Enter your field area and choose the climate band matching your season.
  2. 2Select your irrigation method and soil texture.
  3. 3Read the seasonal water volume, peak daily demand and irrigation interval, then follow the scheduling note.

Why use Polyhouse tomato Water Requirement Calculator?

  • Uses polyhouse tomato's real FAO-56 Kc curve, not a flat factor
  • Accounts for drip / sprinkler / pivot / surface efficiency
  • Gives seasonal volume, peak daily need and an irrigation interval
  • Free, instant and fully in-browser — works offline in the field

Frequently asked questions

How much water does polyhouse tomato need?+

Protected (polyhouse) tomato uses ~25–30% less water than open field for the same crop, delivered precisely by drip fertigation. The exact figure depends on climate and season length; this tool sums ET₀ × Kc across the crop's 200-day growth stages for your conditions.

Does polyhouse tomato need less water than open field?+

Yes — the sheltered environment lowers evaporative demand (ET0) by roughly 25–30%, so the same crop needs proportionally less water, delivered precisely through drip fertigation.

How is polyhouse tomato irrigated?+

Almost always by drip fertigation in daily (often multiple) small doses, matched to the lower indoor ET0 and the long indeterminate crop that fruits for many months.

What is ET₀ and Kc?+

ET₀ (reference evapotranspiration) is how fast a standard grass surface loses water in your climate. Kc (crop coefficient) scales it to a specific crop and growth stage. Crop water use ETc = ET₀ × Kc — the basis of FAO-56 irrigation scheduling.

Is this calculator free and private?+

Yes — free, no sign-up, and all calculation runs in your browser, so it works offline in the field and your data never leaves the device.

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