Vegetable Gardens Need How Much Water Per Week?

How Much Water Per Week

• The amount of water you give your vegetable garden a week depends on the weekly rainfall. Typically, vegetable gardens need 1 inch of water a week, according to North Carolina State University. To check the amount of rainwater your vegetables receive every week, place a tuna can in the garden. A tuna can is 2 inches in height; if it fills 1/2 full, you don't have to water your plants. If the can fills 1/3 of the way, your plants need additional water.

Root Depth

• Spraying water over the gardening area may not give your vegetables 1 inch of water. Water not applied deeply results in evaporation; the water needs to reach the plants' root systems. Vegetables grow their root systems in varying depths. For example, radishes and lettuces grow roots at a depth of 12 inches, carrots and eggplants grow roots at 24 inches and pumpkins and watermelons have roots systems at depths of 36 inches.

Watering Deeply

• To achieve deep watering, water must be applied slowly through the sprinkler system. Find out how much water your sprinkler system applies to the vegetable garden by turning the system on and placing a tuna can in with the plants. Keep track of how long it takes for the can to fill halfway. Dig to a depth of 24 to 36 inches to see if the soil is moist at the bottom.

Other Irrigation

• As alternatives to a sprinkler system, use a drip system or soaker hose to apply 1 inch of water a week. A drip system applies an even amount of water, but is more costly than a soaker hose. A soaker hose waters the garden deeply, but cannot be used on rows longer than 25 feet or uphill, according to the University of California. Mulching around your vegetable plants helps lock in moisture and prevent water evaporation.