For overhead or sprinkler watering, adjust the rate of water application to about 1/2 inch per hour. A faster rate will cause run-off unless your soil has exceptionally good drainage. To determine the rate for a sprinkler, place small cans at various places within the sprinkler's reach, and check the level of water in the cans at 15-minute intervals.

When using the oscillating type of lawn sprinkler, place the sprinkler on a platform higher than the crop (to prevent water from being diverted by plant leaves), and try to keep the watering pattern even by frequently moving the sprinkler and overlapping about half of each pattern.

Wet foliage overnight can encourage diseases, so do not use sprinkle irrigation in the evening. Morning watering is preferred as there will be less water lost to evaporation than in the heat of the day. Add enough water to soak the soil to a depth of 5 to 6 inches. The amount required varies with the nature of your soil. Frequent, light waterings will encourage shallow rooting which will cause plants to suffer more during drought periods, especially if mulches are not used. On the other hand, too much water, especially in poorly drained soils, can be as damaging to plant growth as too little water; it deprives the roots of oxygen needed to grow.

By knowing the critical watering periods for selected vegetables or vegetable types, you can reduce the amount of supplemental water you add. This can be important, especially where water supplies are limited. In general, water is most needed.