Horticulture
Fact Sheet
Horticulture
Fact Sheet
Wayne J. McLaurin, Extension Horticulturist
All vegetables, especially tomatoes, like an even supply of water throughout the season -- and if their water supply fluctuates, they'll develop problems. However, if watering restrictions or bans are imposed, water conservation is a critical issue.
There are many ways to conserve water in the vegetable garden. One is to cut the top from gallon-size milk jugs, punch very small holes in the bottoms, and set them in the ground with only the neck showing above the surface. Use one jug near (or between) each large (tomato or squash) plant and fill it once or twice a week or more often if needed. When the plants start fruiting (fruits are the size of a quarter), add one or two teaspoons of a complete fertilizer, such as 5-10-10, to each jug once a week. You can use large cans in place of jugs.
Once the soil is moist, mulch will help prevent water loss caused by evaporation. Organic mulches reduce the fluctuation of soil moisture and help keep the soil cooler during the summer. In addition, mulches have the added benefit of serving as a barrier to certain soil-borne diseases. Spread organic mulches such as leaves, bark or week-free hay 3 to 4 inches thick to prevent sunlight from reaching weed and grass seeds. Newspaper, three sheets thick, placed on the soil with organic mulches on top will also conserve moisture and act as a weed barrier.
The greater the amount of organic matter in your soil, the better the water-holding capacity it will have. Organic matter in the soil and a mulch on top greatly increase a soil's ability to use water efficiently.
If possible, apply irrigation in a manner to keep plant foliage dry. Ooze or drip hoses are ideal for this. If overhead applications are made, apply in time for the foliage to dry completely for one ro two hours before nightfall. Shallow rooted crops, such as beans and greens, should be watered more frequently with lighter applications than deep rooted crops like sweet corn and tomatoes. Deep rooted crops require more water but less frequent applications.
Do not stand in the garden and spray the plants lightly every day. This is the worst possible way to water. When you water, water thoroughly to encourage roots to seek water and nutrients deep in the soil. With an extensive, deep root system, plants are better able to withstand dry periods. When watering, soak the soil to a depth of at least 6 to 8 inches. A thorough soaking every four or five days on light, sandy soils and every 7-10 days on heavy clay soils is a good general guide for irrigating vegetables in the absence of rainfall.
Vegetables like moisture, but over watering is harmful. Over watering not only wastes water, it also prevents the roots from getting air. If your plants look wilted on a hot summer afternoon, that's normal. They will usually perk up overnight. If plants are wilted in the morning, don't wait -- water.
Watering early in the day reduces evaporation loss and allows plant foliage to dry quickly. Wet foliage overnight may encourage some diseases. Drip irrigation or soaker hoses deliver water right at the soil surface and not on the leaves, so you can water most any time. Avoid watering at mid-day; evaporation losses are highest at this time. Also, do not water when there is wind; you can lose up to 50 percent of the water.
Use soaker hoses or drip irrigation. These two methods conserve water by allowing water to be placed near the plant and you don't have to water the row middles. These two methods also allow the plant to remain dry, which helps eliminate disease problems.
If you use overhead sprinklers, try to water on cloudy days. Don't water when a strong wind is blowing, since this can cause uneven water patterns. Very early morning watering can be helpful, especially if the plants are already wet from dew. If you water late in the afternoon, plan to finish in time to allow plants to dry off before nightfall.
Resist cultivating the soil. Any stirring of the soil will increase moisture loss. Dry weather
usually reduces weed growth, so don't cultivate unless absolutely necessary. If cultivation is
required, plow as shallowly as possible and try to leave the surface as smooth as possible.
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