💧Garden Watering Calculator
sq ft
inches

Weekly Water Needs

Water to apply—
Total weekly need—
Rainfall covers—
Equivalent depth—

Related Calculators

How Much Water Does a Garden Need?

Most vegetable gardens need 1 inch of water per week — either from rain or irrigation. One inch of rain over one square foot equals about 0.623 gallons.

The formula

Gallons needed = Area (sq ft) × Depth (inches) × 0.623

This calculator adjusts for crop type and climate multiplier, then subtracts expected rainfall to give you just the irrigation amount.

Water needs by crop

CropInches / week
Tomatoes1.5 – 2
Lettuce, spinach1 – 1.5
Cucumbers1.5
Beans1
Corn1.5 – 2
Herbs0.5 – 1
Root vegs0.75 – 1
Best time to water: Early morning (6–10 AM) reduces evaporation and prevents fungal disease. Avoid evening watering which leaves foliage wet overnight.