There is no doubt that all life is dependent on water. Yet, in recent years as we have grown the garden there seemed to be either too much or too little. While we are essentially helpless to control too much water, we can add water to maintain production through dry periods. It is not hard to see why water is so important to our vegetables as we look at their water content. Cucumbers contain about 96%, melons from 92 to 94%, tomatoes have 94%, summer squash has 95%, snap beans 89% and sweet corn 74%. The large amount of water they contain is not hard to understand since all life processes depend on water.
An inadequate water supply can not only reduce production, but cause other problems. Blossom-end rot of tomato is partially a response to water stress as well as bitterness in cucumber, premature drop of squash, and poorly filled ears of sweet corn. In many vegetables, the most critical time for adequate water is the period between flowering and fruit maturity. Pepper and tomato need plenty of water at all stages, corn needs the greatest abundance during the silking and tasseling stage, and cucumbers need the most water from flower pollinating until fruit is developed. Onions and some of the melons need plenty of water until they near maturity. At that point water should be reduced.
Irrigation systems can be a bear to put together. But this segment will show you an easy and fast way to get your garden watered in no time.
Even though we know how important water is, there are times when it is difficult to keep an adequate supply in the garden. Water shortages, vacations, or the cost of watering may sometimes make it impossible to continue. When it is not possible to irrigate because of one of these factors or because of a long distance from a water supply, fairly heavy mulches can help conserve the natural water supply. The time of day that a garden is irrigated may also help to increase efficiency or reduce cost. During very hot weather, the most efficient watering time is at night when evaporation loss is low, particularly when overhead sprinkling is used. Overhead irrigation is best done toward morning when leaves will dry quickly as the sun hits them. This is most essential for vegetables very susceptible to leaf diseases. At night there is also less demand on water systems and the water pressure is better.
The next best time for overhead watering is in the evening, although plants subject to leaf diseases can be more seriously damaged by evening watering since foliage will stay wet for longer periods of time. When soaker hose or trickle irrigation methods are used, leaf wetting is not critical, but soil surface evaporation is still less in the cooler evening, night and early morning.
During normal summer temperatures about an inch of water is needed per week. This may be applied in one or two applications. As temperatures rise and are maintained in the 90′s, this amount can be increased to 1 1/2 or 2 inches per week. To apply an inch of water to 1,000 square feet, 627 gallons of water are needed. For smaller areas this amounts to about .6 gallon per square foot. How long it will take to apply this amount or any amount will depend on the water pressure as well as the diameter and length of a hose. Roughly, using a 50 foot long hose that is 1/2 inch in diameter at 40 pounds per square inch pressure and using a sprinkler that could cover the entire area, watering would take about 2 hours. An inch of water should wet a good loam soil to a depth of about 6 inches. It will move less deeply in heavy clay soils and deeper in sandy soils.
Trickle irrigation has become a much more common and efficient means for watering. It can cut water use by 20 to 50 per cent. For closely spaced vegetables, emitters are placed about every 12 to 16 inches. Where vegetables are grown in hills or widely spaced, emitters are placed at every plant or hill. In sandy soils emitters need to be placed closer than in clay soils. Emitters vary in size and delivery, but a delivery of about 1/2 gallon per hour is often used. To maintain a more uniform moisture supply with this method, watering for 1 to 1 1/2 hours is often adequate for vegetables. In hot weather and without rainfall, the interval may need to be as frequent as every other day. Generalizations are hard to make for trickle irrigation systems. Be sure to follow directions from the manufacturer of the system you might select.