Water Conservation
CONSERVING WATER IN THE HOME LANDSCAPE
By: Robert J. Black and Jim Midcap
Water is the lifeblood of plants. It is needed for seed germination, plant growth, photosynthesis, transport of nutrients, and control of plant temperature. Water also maintains turgidity of leaves enabling them to retain their shape.
The demand on Florida's limited water supply increases steadily as the population continues to grow and the state becomes more urbanized. This problem is further compounded as a result of salt water intrusion into fresh water wells. If homeowners are to continue to water plants in their landscapes, they need to practice water conservation now rather than waiting until an emergency condition exists.
Normal rainfall in Florida averages from near 52 inches on the central and northern peninsula to near 65 inches in the panhandle west of Tallahassee and along the southeast coast south of Lake Okeechobeemore than one-half of the annual total falls on the central and southern peninsula from June through September. During winter and spring, lack of rainfall may be a serious problem. Even during the rainy season, loss of water from plants and the soil (evapotranspiration) may be so great that supplemental watering is often necessary. Soils which have a low water holding capacity make irrigation essential during periods of low rainfall.
It is difficult to give specific rules on watering because when to water and how much to water depends on the plant species, type of soil, time of year and weather conditions. However, the following guidelines should help in answering these two important questions.
When to Water
Water only when plants need watering. Use a coring device or shovel to dig down in the soil to see if it is wet or dry. If the soil in the root zone feels dry and crumbly, additional water is needed.
Keep a close watch on the lawn. If it looks as though it is wilting, it needs water. If the edges of the grass leaves start to curl and take on a dull bluish-gray color, water the lawn immediately.
Lawns should be watered in late evening, at night or early morning, when winds and temperatures are low. Late morning, mid-day, and afternoon irrigation usually results in loss of water from evaporation. Also strong winds are more likely to blow at these times, resulting in poor distribution of water over the lawn.
How Much Water to Apply
When watering, give the soil a thorough soaking. Frequent, light sprinklings waste water and do little to satisfy the water requirements of a plant growing in a hot, dry soil. Watering in this manner often promotes shallow root systems which increase susceptibility to damage if watering is omitted for a few days.
Wet the soil to a depth of six to eight inches. This type of watering allows the moisture to penetrate into the soil where roots can readily absorb it. A general rule is to apply from one-half to one inch of water every two weeks in winter and once each week in summer. However, because all soils and plants are not alike, some adjustments in the amount of water applied may be needed.
To determine when a sprinkler has delivered once inch of water, place cans or cartons at intervals in the spray pattern, and water until the water level in the cans averages one inch.
Methods of Watering
Water should be applied only as fast as the soil will absorb it. Watering with a hose nozzle turned on full force can do more damage than good. Fast-flowing water runs off quickly carrying soil with it and exposing plant roots to the sun. More efficient watering can be accomplished with soaker hoses and sprinklers. Soaker hoses do a good job, but they don’t cover as large an area as sprinklers.
Another method of watering is drip or trickle irrigation. Drip irrigation supplies plants with constant moisture at a low delivery rate through the use of low pressure plastic tubing installed on or below the ground surface. Low pressure nozzles (emitters) attached to plastic tubing release water at a slow rate into the soil around a plant. By wetting only the root zone area of the plant, there is a dramatic saving in water, weeds are not encouraged to grow and plant growth is accelerated. This increased growth occurs because the plant is not subjected to wet and dry cycles which normally occur with other irrigation methods.
The water lance and the ponding method are good ways of watering trees and shrubs. A water lance is a sharp pointed tube attached to a water hose which is used to inject water near the root system of a plant. The water should be injected very slowly because a strong stream may dig sub-surface holes causing air pockets which damage roots. Ponding is a common method of watering newly-planted trees and shrubs. A pond is a saucer basin built by making a ring of soil two to three inches high around a plant. A slow-running hose or soaker hose can be used to fill the pond.
Drought Tolerant Plants
Another approach to conserving water in the home landscape is using drought tolerant plants. In areas where there is difficulty in applying sufficient water such as sandy soil or a terrain where the water drains off too quickly, drought tolerant plants are an alternative. Areas of the yard too far to reach with a hose for convenient watering are also places for drought tolerant plants.
TIPS ON CONSERVING WATER
- Remove thatch from turf - a thick thatch layer restricts water movement into the soil.
- Increase mowing height of lawns - This increased height allows the plant to develop a deeper root system.
- Control all weeds - Weeds exhaust water which may be needed to keep plants alive.
- Reduce fertilizer applications - Fertilizer promotes growth and will increase the need for water.
- Prune. If water supply is so limited that literal survival of plants is in question, appreciable pruning can be done at the peak of the water shortage.
- Soil improvement - The addition of organic matter (peat, compost, well-rotted manure, bark, etc.) to sandy soil will increase its water retention and therefore reduce the frequency of watering.
- Mulch - Use 2 inches of mulch on annual bed areas and around trees and shrubs.
- STRETCH the number of days or weeks between watering to the longest suitable interval.
- Soak deeply.
- Cull out poor woody plants - Don't waste water caring for marginal or undesirable plants.
- Use waste water free of harmful compounds (Borax, trisodium phosphate, etc.)
- Adjust sprinklers to avoid waste to sidewalks, streets, and gutters.
- Keep sprinkler heads clean to assure even distribution of water.
- Check hose and faucet washers annually.
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