As you drink your recommended 6 to 8, 8-ounce glasses of water per day, don’t forget that your vegetable garden should also never be short of water this summer. Did you know that water makes up 80 to 90 % of vegetable and fruit weight? Water affects yield, fruit size, and quality. It also prevents a variety of disorders such as toughness, off-flavor, cracking, blossom-end rot, and misshapen fruit.
Other than the first few weeks after seed germination and immediately after transplanting, vegetables have certain “critical stages” in their growth and development when water is extremely important. For example, lima, pole, and snap beans need water when they’re flowering. Sweet corn should have adequate water available during silking, tasseling, and ear development. Keep cucumbers and squash well-watered during flowering and fruit development. The same advice applies to eggplant, pepper, and tomato, which require adequate water from flowering until harvest.
The rule of thumb for watering vegetable gardens is simple: vegetables need an inch of water per week in the summertime, whether it’s provided by you or Mother Nature. (Use a rain gauge to help determine the amount of rain you have received each week). This converts roughly to six gallons per square yard per week. This inch of water will wet the root zone to a depth of 6 to 8 inches.
Don’t wait for your vegetables to signal their need for water with wilted leaves or young leaves that have become dull-colored, darkened, or grayish. They could already be injured when they show these signs of drought stress. Yield and quality could also already be compromised.
In addition to monitoring weekly rainfall amounts, check the soil for moisture. With a trowel, dig down 2 to 4 inches deep and feel the soil. With Piedmont clay soils, you’ll find that simply not being able to dig down easily is enough to know that it’s dry.
Shallow-rooted vegetables will have a greater demand for water than deep-rooted crops, so keep a watchful eye on them. A few shallow-rooted crops include lettuce, corn, potato, and radish. Moderately deep-rooted vegetables include bean, carrot, cucumber, eggplant, cantaloupe, pepper, pea, summer squash, and turnip. Deep-rooted vegetables include asparagus, lima bean, pumpkin, winter squash, sweet potato, tomato, and watermelon.
You can irrigate your vegetable garden with a variety of tools, including a watering can, a garden hose with a fan nozzle or spray attachment, a moveable lawn sprinkler, a soaker hose, or drip or trickle irrigation. If you want to be conservative about the amount of water you apply to your vegetables, consider drip or trickle irrigation, which is the most efficient irrigation method available. For more information about watering your vegetable garden, see HGIC 1260, Watering the Vegetable Garden.
To help conserve moisture in the soil, maintain a shallow layer of mulch around your plants. Before you start your fall vegetable garden next month, add organic matter to the soil. Organic matter, such as compost, increases the moisture-holding capacity of the soil. For more information on mulch, see HGIC 1604, Mulch.
Finally, when you water your vegetables, don’t go overboard and give them more than necessary. Besides being wasteful, excessive watering leaches nutrients out of the soil, encourages diseases, and may reduce flavor, especially in cantaloupes and watermelons.
Although keeping up with the watering needs of your vegetables may be an unglamorous chore, it’ll be worthwhile at harvest time. Your vegetables will not only have the look and size of those in the supermarket, but they’ll have that home-grown, fresh-picked flavor.