Watering Plants and Drip Irrigation

When it rains, it pours, but when the weather is dry, a drip is enough. This is a very appropriate time to discuss water needs because, pretty soon, you will need water—and lots of it!

How will your plants survive, or should I say, “will your plants survive”? Since most of us are self-made paupers, money is a commodity that is usually in short supply. Water is a necessity for all life, but people hate to spend money for the most precious of all liquids. Yet, these same people will go on a boozing binge and spend enough in one night to water plants for 6 months!

Obviously, I am not going to reform the boozers, but maybe I can save some plants from desiccation. The only fate worse than thirst for a plant is death. In fact, they often accompany one another! Even if some folks are wise enough to know when to water a thirsty plant just seconds before it crosses death's threshold, these procrastinators are still losers. When a plant thirsts and is severely stressed, overall vigor and production is decreased. This is especially true of plants that are expected to produce fruit. Not only will total yield be decreased, but fruit quality will also decline. Carrots, onions and tomatoes start cracking! Eggplant fruit gets bitter! Shrubs mysteriously die! Flowers bloom with mediocrity! Trees do not grow rapidly! The house's foundation cracks! What is causing all of these calamities? Lack of and improper application of water is the culprit of all of these problems.

Most people don't intentionally make their plants suffer. There are three categories in which the thirst inflicters fall -- those who don't know when to water, those who don't know how to water and those who are so absent-minded they forget. Some may qualify for more than one of these categories.

How do you know when to water? Some people say water when the plant wilts. When a plant wilts, it is obviously in a stressed condition and the damage (foliage burn, foul-tasting fruit, production loss) has already occurred. Besides, does the wilting of a plant indicate drought? I have seen wilted plants standing in water, i.e., they were water-logged. Plants wilt with root rot diseases. So wilt is the worst possible indication. Soil moisture is the best criterion for watering. If the soil moisture is adequate, don't water, even if the plant is wilted. To test for soil moisture, probe around plants with your finger. If the soil is moist several inches deep, your plant is okay.

Rooting depth is the most limiting plant characteristic in relation to water uptake.

Crops with shallow root systems, such as onions and celery, require more frequent irrigations than deep-rooted crops such as pumpkins, tomatoes, and watermelons.

Very shallow rooted crops include celery, lettuce, onion, radish; shallow-rooted crops include broccoli, cabbage, cauliflower, Chinese cabbage, cucumber, muskmelon, pepper (transplanted), spinach, and tomato (transplanted); intermediate rooted crops include bean (snap), beet, carrot, eggplant, pea, pepper (seeded), rutabaga, and summer squash; deep-rooted crops include asparagus, beans (lima), parsnip, pumpkin, winter squash, tomato (seeded), and watermelon.

The most critical stages of growth for vegetable crops and when moisture stress is the most damaging to yields are asparagus (fern growth), snap bean (pod-filling), broccoli (establishment, head development), cabbage (establishment, head development), carrot (establishment, head development), cauliflower (establishment, head development), celery (establishment, rapid growth during hot periods), sweet corn (tasseling, silking, and ear filling), cucumber (flowering, fruit enlargement), eggplant (flowering, fruit development), lettuce (head development), muskmelon (flowering, fruit enlargement), onion (bulb enlargement), pea (flowering, pod-filling), pepper (transplanting, fruit set and development), squash pumpkin (flowering, fruit development), radish (root enlargement), summer squash (flowering, fruit development), tomato (flowering, fruit set and enlargement) and turnip (root enlargement).

Now that you know when to water, you may not know how. The "how" may be the most important part. First of all, plants need to be deep watered to stimulate a larger root system. This larger root system will be advantageous in utilizing every drop of available moisture during periods of severe drought. Deep watering involves soaking.

Floor or furrow irrigation, a technique used by many gardeners, involves mounding the soil into raised beds and running the water down the furrows between the beds. The bed centers or rows are spaced at least 30 inches apart. The bed soil is firmed to enable it to conduct water to the top of the bed. In this way, moisture will reach the roots of young plants. The ditches or furrows between these rows are "flooded" or filled with water. The roots of the plants growing in rows on the beds have direct contact with the water supplied. This technique results in deep soaking that encourages vigorous development of root systems.

The most obvious disadvantage of this type of irrigation is water waste. The system involves wetting the entire garden rather than just the area where plants are growing. A sprinkler system also has the added disadvantage of wetting plant foliage, which can encourage plant diseases.

Gardeners have an easier way to deep water. It is called drip irrigation. "Drip” or “trickle" irrigation is a unique method of irrigation. It allows precise applications of water in the immediate vicinity of plant roots. Soil moisture in the area around the plant is maintained at a uniformly high level throughout the growing period. Small amounts of water are applied frequently, perhaps daily, to replace that withdrawn by soil evaporation and plant transpiration. Growth and production of a plant is greater when they are not subjected to the wet and dry cycles that normally occur with other irrigation methods. This is very apparent in situations where plants are growing near a leaking faucet. Such plants always out perform neighboring plants.

This has often been verified in tests throughout the country. Data indicate that tomatoes can yield 30 to 40% more fruit and peppers as much as 30% more fruit when grown with drip irrigation. Drippers are excited about the possibility offered by a drip irrigation system. One possibility is increased yield because of a constant water supply. The use of drip irrigation enables a gardener to keep plants moist but never too wet or too dry. This is an important concept. In an article which appeared in the Progressive Farmer, entitled "How to Grow 300-Bushel Corn," the statement is made that "if corn is allowed to stress for just 2 days, you can lose 2 bushels per acre per day."

Of course, few of us have an acre of corn, but the concept of yield reduction applies to small gardens as well. The operation of a drip system for 3 hours per day every other day will insure that adequate moisture is present. All of this increase in production occurs even though much less water is used. Distribution and evaporation losses are minimized. Less of the total soil area is fully wetted than with sprinkler and furrow systems. Normally, only 25% of the soil surface is wetted with drip. This significantly reduces the amount of water required for irrigation.

Drip irrigation also simplifies your irrigation procedures and reduces labor. This is imperative if you have a family which is allergic to dirt and sweat and who will let plants die of thirst when you are away if an easy watering technique is not available. Drip systems can be easily activated from one faucet. A drip irrigation system also takes care of the third category of thirst “inflictors”—those who "forget" to water certain plants. Once the drip hose is installed around shrubs and vegetables, it never "forgets" to water. In fact, it specifically waters each and every plant. Of course, you must remember to activate the drip system for 3 hours a day every other day by turning the water faucet on. If you can't remember that, then you are too derelict to be entrusted with plants anyway!

So, before the dry weather destroys your plants, spread a little happiness around. Install a drip system!