Keith Hansen

As the temperatures rise and rainfall remains scant, water for the lawn and garden become more important. Many areas of the region are behind on annual rainfall, and wilting plants and wilted spots in the lawn become noticeable.

While we need to be sure our landscapes do not suffer, at the same time we do not squander or waste our water in the process. We need to be good stewards of this precious natural resource. The cities of Bullard and Whitehouse both implemented water rationing this week to relieve peak loads on their water delivery systems.

Here are a few suggestions for landscape irrigation. If any suggestions are radically different from your current practices, be advised to make any changes slowly at this time of year to avoid placing your plants under further stress.

Any plant, whether native, drought tolerant or not, will need special care for the first two years after planting. So, pay attention to your young plant's water needs, especially during hot, dry summer weather.

You were created with a built-in water meter - your index finger. Physically check both the original soil ball that came with the plant, and the soil surrounding the plant, to determine the moisture status. It's possible for the surrounding soil to be soaking wet while the original root ball is very dry. You may need to hand water some plants to assure the original root ball is getting sufficient water.

Keeping the soil too wet is not good for plant development. Continuously wet soil surrounding newly planted shrubs and trees can inhibit the development of new roots into the surrounding soil because oxygen is depleted from constantly saturated soil. The soil should be moist, not soaking wet.

Of the large amounts of water applied to lawns and gardens, a lot of it may never be absorbed by the plants and put to use. Some water is lost to runoff by being applied too rapidly, and some water evaporates from exposed, unmulched soil. But the greatest waste of water is applying too much too often.

In addition to over watering plants, excessive irrigation can leach nutrients deep into the soil away from plant roots, increasing the chances of polluting groundwater. Runoff caused by excess irrigation can carry polluting fertilizers and pesticides to streams and lakes.

Many lawns receive much more water than what is needed for a healthy appearance. The key to watering lawns is to apply water infrequently, yet thoroughly. This creates a deep, well-rooted lawn that efficiently uses water stored in the soil.

Frequent, light sprinkling promotes a shallow root system that is much more susceptible to environmental stresses like heat, drought and cold.

To know when, or how often, to water the lawn, observe the grass. Wilting and discoloration are signs of water stress. At the first sign of wilting, you have 24 to 48 hours to water before serious injury occurs. If wilted conditions continue after irrigation, check grass for chinch bugs, and your irrigation system for inadequate coverage due to misaligned or plugged heads. By careful observation, you can determine the frequency for irrigation based on your type of soil and the current environmental conditions. There is no need to water every other day, just because you can.

Most soils need about 1 to 1 1/2 inches of water per week to supply the potential root system of a turf grass. Use rain gauges or catch pans to measure how much water your sprinkler heads put out over a certain period of time. That will help you know how long to run your system to deliver the correct amount of water. Depending on your soil type, you might water as infrequently as once per week on heavy textures soils, or as frequently as every few days for sandy soils.

All established trees, shrubs and groundcovers should be watered deeply, yet infrequently, in the absence of rain. Every three to four weeks, give them a thorough, deep watering. The major portion of the feeding root system of a tree or shrub is located within the top 12 to 18 inches of the soil and near the drip line of plant. The drip line is the area directly below the outermost reaches of the branches. Apply water in a band at the drip line, not at the trunk.

Sprinkler irrigation is the most commonly used method of landscape watering. The two most common types of sprinkler irrigation systems are the hose-end sprinkler and the permanent underground systems.

If you have a permanent system, occasionally check it to make sure the sprinkler heads are not broken or clogged, and are properly adjusted to avoid watering driveways and sidewalks.

With either hose-end sprinklers or permanent systems, water between late evening and mid-morning to avoid excessive waste through evaporation during the heat of mid-day.

Drip or trickle irrigation can offer increased watering efficiency and plant performance when compared to sprinkler irrigation in some cases. Drip irrigation slowly applies water to the soil. The water flows under low pressure through emitters, bubblers or low-flow spray heads placed near each plant. Water applied by drip or trickle irrigation has little chance of waste through evaporation or runoff.

Experiment with drip irrigation products in small areas of the landscape to become familiar with this water-saving technique. Shrub and flower beds and vegetable gardens are good candidates for drip irrigation.

Proper landscape maintenance can help reduce the water needs of your plants. Apply fertilizer at the proper time and do not use too much at any one time. Slow-release formulations keep plants healthy without stimulating excessive growth which increases plant requirements for water. Don't fertilize lawns during a drought. Mowing height and frequency will also affect your lawn's water needs and health.

Finally, keep your landscape free of weeds which compete with your plants for water and nutrients. A layer of mulch over the surface of the soil around plants not only reduces weeds, but also stops water loss through evaporation.

PERMANENT SPRINKLER SYSTEM
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