Nothing makes me crazier than seeing sprinklers running in the middle of the day or at night. Ninety-nine percent of folks don't know how to water their gardens. So people, here are the rules. Follow them and save money, time, and water. And, your plants will be much happier and healthier.--R
1. For established plantings, deep, infrequent watering is recommended. In most cases, an inch of water per week (rain plus irrigation) should be sufficient. Applying that inch of water in one deep watering will encourage deeper rooting, which leads to stronger, healthier plants. Watering once a week also fits well into most municipal water restrictions. Shallow, frequent watering, on the other hand, will lead to shallow root systems and high water loss through evaporation. With shallow watering, such as light frequent sprinkling, you actually end up wasting quite a bit of water and still don’t meet the needs of your plants.
2. The best time of day to water is early morning before the temperatures begin to rise. This gives the plants a good supply of water to face the heat of the day. Early morning also tends to be a time of lower winds and thus reduced evaporation. If watering cannot be done in the early morning, very late afternoon is also satisfactory. It is important to water early enough so that the leaves have time to dry before nightfall to avoid development of fungal diseases. If possible, choose watering methods that will not wet the leaves (such as soaker hoses) and thus allow for late evening watering.
3. There may be need to evaluate the device used for watering. While a lawn sprinkler may be a good method for the lawn, it may not be the best way to water a vegetable garden. Pick a watering device that matches the needs of your garden and the time you have available to water. Once a device is selected, know the correct way to use that device, in order to water efficiently.
A. Oscillating lawn sprinklers are the most common used devices for watering lawns. The drawback to them is that up to 50 percent of the water put out can be lost to evaporation or drift. Water may also be delivered unevenly to lawns, since more water is dispensed near the sprinkler. The sprinkler must be moved around to provide even watering over the entire lawn. You can measure the output of these sprinklers by putting out a straight-sided can and measuring the water that accumulates in it.
B. Root feeders have become popular for watering trees and shrubs. These can be useful devices, but they must be used properly. The roots that are active in water uptake are not found near the trunk, but rather out at the dripline and beyond. Therefore, the root feeder should be used away from the trunk to be effective. Many people put the root feeder too deeply into the soil. Most of the roots in a tree or shrub’s root system will be in the upper 12-18 inches of soil. The root feeder should be inserted so that water is delivered to that area.
C. Soaker hoses have also become very popular. They can be very effective devices for watering vegetable gardens and flowerbeds. Soaker hoses allow water to weep out gently over the entire length of the hose. The benefit to using these hoses is that the leaves are never wet, reducing the possibility of diseases. The water goes right to the root system where it is needed and very little is lost to evaporation. Soaker hoses must be left on for a length of time to water deeply. An inch of water penetrates about six inches in a clay soil. Let your hose run for a while, then dig down with a trowel to see how deep the water went. If it is less than six inches, the hose needs to run longer.