Most gardens need about 1 inch (25 mm) of water a week, but heat, soil and the type of plants change that a lot. Enter the size of the area, what you grow, your soil and this week’s weather. The calculator gives you the weekly amount, how many times to water and how long to run a hose, sprinkler or drip line.
Watering Calculator
Enter your area, plants, soil and weather to see how much water to give each week, how often, and for how long.
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How the calculator works
It starts from the typical weekly need for each kind of planting, adjusts for temperature, subtracts any rain you enter and then splits the total into sessions based on your soil. Sandy soil drains fast and needs smaller, more frequent watering; clay holds water and does better with one deep soak.
- 1 inch of water over 1 square foot is about 0.62 gallons (2.4 liters).
- A typical garden hose delivers about 5 gallons (19 liters) a minute at full flow.
- A drip line uses up to half as much water because it goes straight to the roots. See our drip irrigation guide.
Plants still wilting after you water? Check the Plant Doctor or our guide to yellow leaves, as overwatering causes many of the same symptoms as drought.
Frequently asked questions
How long should I water my vegetable garden?
For an 8×4 ft bed needing 1 inch a week, that is about 20 gallons, or around 4 minutes with a hose split over two sessions. A sprinkler takes much longer, around an hour per session, because it puts water down slowly.
Is it better to water in the morning or evening?
Early morning is best. Less water evaporates, and leaves dry quickly during the day, which helps prevent fungal diseases like powdery mildew.
How do I know if I watered enough?
Push a finger or a trowel 2 inches (5 cm) into the soil an hour after watering. It should be moist at that depth. If it is still dry, water a little longer next time.