Garden Watering Schedule Calculator Formula
Understand the math behind the garden watering schedule calculator. Each variable explained with a worked example.
Formulas Used
Weekly Watering Needed
gallons_per_week = deficit_inches * garden_area_sqft * 0.623Irrigation Deficit
deficit_display = deficit_inchesSprinkler Time (at 1 GPM)
minutes_sprinkler = deficit_inches * garden_area_sqft * 0.623Variables
| Variable | Description | Default |
|---|---|---|
garden_area_sqft | Garden Area(sq ft) | 200 |
weekly_need_inches | Weekly Water Requirement(inches) | 1.5 |
weekly_rainfall_inches | Weekly Rainfall(inches) | 0.5 |
deficit_inches | Derived value= max(weekly_need_inches - weekly_rainfall_inches, 0) | calculated |
How It Works
Garden Watering Needs
Most gardens need 1-1.5 inches of water per week from irrigation and rainfall combined. The deficit must be made up with supplemental watering.
Formula
Deficit (inches) = Weekly Need - Rainfall
Gallons = Deficit (inches) x Area (sq ft) x 0.623
The factor 0.623 converts inches of water over square feet to gallons (1 inch over 1 sq ft = 0.623 gallons). Water deeply and less frequently to encourage deep root growth.
Worked Example
A 200 sq ft garden needing 1.5 inches/week with 0.5 inches of rain.
garden_area_sqft = 200weekly_need_inches = 1.5weekly_rainfall_inches = 0.5
- 01Deficit = 1.5 - 0.5 = 1.0 inch
- 02Gallons = 1.0 x 200 x 0.623 = 124.6 gallons per week
- 03At 1 GPM sprinkler: about 125 minutes of watering
Ready to run the numbers?
Open Garden Watering Schedule Calculator