Garden Watering Calculator
Enter your garden's size and how many inches of water it wants each week, and it converts that into gallons — so you know what you're actually pouring on.
Most vegetable gardens want about an inch of water a week. One inch over a square foot is roughly 0.623 gallons, rain included.
How it works
Watering advice comes in inches, but hoses and cans measure gallons, so we bridge the two. One inch of water spread over a single square foot works out to about 0.623 gallons.
Multiply your garden's area by the inches you want and by 0.623 to get gallons. An 8-by-4 bed getting one inch a week needs roughly 20 gallons — a number you can actually plan around.
Rain counts toward that inch. If a storm drops half an inch, you only owe the garden the other half, which is where a cheap rain gauge saves you both water and money.
Frequently asked questions
How much water does a vegetable garden need?
About an inch a week is the classic target for most vegetables, from rain and hose combined. Sandy soil and hot spells push that higher; cool, cloudy stretches let you back off.
Where does the 0.623 come from?
It's the conversion for one inch of water over one square foot. Run the volume in cubic feet through the 7.48 gallons in a cubic foot and it lands right around 0.623 gallons.
Is it better to water deeply or often?
Deep and less often, as a rule. A good soak drives roots down where the soil stays moist, while daily sprinkles keep roots shallow and leave plants helpless the moment you skip a day.
Does rain count toward the weekly total?
It does, and you should subtract it. Keep a rain gauge in the garden, and on weeks a storm delivers part of the inch, just top up the difference instead of watering the full amount.