Watering Lawns
Avoid wasting water when watering your lawn. Irrigate with an inch of water weekly if necessary during periods of no rainfall. Water demand does vary from one lawn species to another. Use a rain gauge to determine the amount of time to water.
Watering Trees and Shrubs
Quite possibly the most critical input in any landscape planting is water, yet it is often one of the most difficult to determine. Newly set shrubs should be watered at least once a week during dry weather. Water thoroughly and deeply. This will promote deep root penetration; shallow watering keeps root systems near the surface. This often subjects the plant to damage from heat and drought. Once plants have become established, they can go for longer periods without water. It is good practice to water beds thoroughly once a week during hot, dry weather.
Watering Annual and Perennial Flowers
Irrigation requirements vary according to the flowering annual and perennial planted. Avoid overwatering. When normal rainfall does not provide adequate moisture (about
½ inch to 1 inch a week), supplemental water is needed. A thorough soaking is preferred instead of frequent sprinklings.
Reducing Water Use in Ornamental Plantings
Home landscapes account for a small but significant amount of water usage in Louisiana landscapes. Careful management can improve the performance of plants and still conserve water. The following pointers can help reduce water usage.
Keep the size manageable. A small garden provides more enjoyment than a large, weedy, poorly maintained planting. Don't feel guilty for not providing everyone in the neighborhood vegetables all summer long.
Add organic matter to the soil. Organic matter such as compost, cow manure, rotted sawdust or hay, or peat moss improves soil when it does rain. Once in the soil, organic matter acts like a sponge, holding water in the root zone where the plants can use it.
Use a mulch. Mulching reduces water demand by as much as 40 percent. Mulches keep the soil cooler, eliminate weed competition and reduce evaporation from the soil surface. Eye appeal is an important consideration for flower garden mulches whereas efficiency and ready availability are more important in the vegetable garden. Good mulches for flower gardens include pine bark, shredded hardwood bard, pine needles and cottonseed hulls. These should be applied at least 2 inches deep for maximum benefit. Black plastic has become popular as a vegetable garden mulch. It is especially beneficial when used with drip irrigation. Good organic mulches for the vegetable garden include old hay, rotted straw or leaves. Dry lawn clippings also make a good mulch, but they usually are best left on the lawn where they fall.
Use wider plant spacings. Crowding plants close together results in intense competition for water. In the flower garden, space annual plants at least 12 inches apart; perennials should be spaced at least 18 to 24 inches apart. In the vegetable garden, use wide row spacing and give the plants more room in the row. Plants should be thinned to have only one plant per hill.
Control the weeds. Weeds, especially grasses such as crabgrass, are extremely aggressive competitors for water. Keep them under control by mulching or by hand cultivation.
Use drip irrigation or soaker hoses to water. These apply water slowly, directly to the soil. This helps ensure that the plants get all of the water. Also, because the foliage stays dry, the incidence of leaf disease is reduced.
Grow plants that avoid the drought. Many flower garden plants have a sufficiently fast growth cycle so that they "do their thing" before the heat of summer arrives. Flowers such as tulips, daffodils, pansies, irises, poppies and columbines complete their life cycle before the heat of summer arrives.
In the summer, grow drought-tolerant plants. Many plants have excellent drought tolerance. Flowers such as lantana, purslane, portulaca, periwinkle and marigolds have excellent drought tolerance. A host of native wildflowers such as purple coneflower, black-eyed Susan, butterfly weed and verbena provide color in the driest years.
Reducing Water Use in Lawns
Drought injury, even on unirrigated turf, need not be overly injurious to the lawn if some precautions are followed before the drought becomes severe. The home lawn can use 80 percent of the water used in the landscape. By reducing water applications to the lawn, significant water savings can result.
Many people water their lawns because they are afraid that if they don't water, their lawn will die. This is simply not the case with most of the warm-season lawn grasses used in studies at Texas A&M showed that functional turfgrass can be retained throughout a 160-day period without using any additional water. Without either rainfall or supplemental irrigation, five different varieties of three warm-season turfgrasses (Bermudagrass, St Augustinegrass and Seashore paspalum) displayed exceptional drought resistance. If not watered in the summer, bermudagrass will usually go dormant. It will begin to regrow when rain returns. While the dwarf hybrid bermudas are not quite as drought tolerant as their robust parent, they are tough enough to survive summer dormancy. The other common lawn grasses used will survive without irrigation when established but are not quite as drought tolerant as bermudagrass.
Too often, poor quality lawns containing a mixture of crabgrass and other grassy weeds are watered. Allowing a low-quality lawn to go dormant will not hurt it and may even improve the lawn. Crabgrass often is shallow rooted and will die out when drought stress becomes too severe, allowing the deeper-rooted bermudagrass to become better established later.
The following procedures help get a lawn through a drought without supplemental irrigation. While warm-season grass will still go dormant during severe drought, these procedures will keep the grass growing longer and provide fastest recovery for the lawn when rains resume.
Avoid high rates of fertility. Fertilize bermudagrass lawns in early April and early June according to the rates recommenced by the parish Extension office. If no recommendations are available, usually 1 pound of nitrogen should be applied per 1,000 sq. ft. of lawn area per application time. Soil testing to determine fertilizer and lime needs more accurately provides the grass just what it needs for optimum growth. Fertilizing at higher rates encourages lots of leaf growth and requires more water. Maintain higher levels of potassium for drought resistance.
Mow the grass high. Common bermudagrass should not be cut shorter than 2 inches high during the summer. High grass permits deep root growth and provides shade for the soil keeping it cooler and reducing evaporation from the soil surface. Deep root growth permits extraction of water from greater depths in the soil.
Use herbicides in spring to reduce competition with weeds. But, be careful not to over-apply preemergence herbicides because they can retard root growth to an extent. Avoid herbicide use from late spring on.
Mow when the grass is 3 inches tall. Delaying mowing until the grass is taller results in the removal of an excess amount of leaf area and causes the grass to go into dormancy sooner. Use a sharp blade. A sharp blade cuts the grass cleanly, leaving less injury and reducing stress, which pushes the grass toward dormancy.
Aerate the soil in spring. This encourages better, deeper root growth and allows faster penetration of water when rain comes. Zoysiagrass lawns should be dethatched every spring to encourage vegetative growth and remove the dense accumulation of debris that prevents deep root development.
Leave some clipping in place. These provide a kind of mulch that reduces soil evaporation of water and insulates the soil from the heat of summer; avoid thatch layers thicker than an inch.
Water lawns well every week or two. More and more homes are equipped with automatic sprinkler systems, but unfortunately most of these are improperly adjusted. Many systems are adjusted to irrigate daily, applying only a small amount of water at a time. This encourages shallow root development, which makes the grass more susceptible to heat and drought stress. On established lawns, watering more than once a week is seldom needed. One inch of water per week keeps a healthy lawn green and growing. Watering at night during droughts reduces the amount of water lost to evaporation. Avoid application rates that result in wasted surface runoff. Run cycles of irrigation if necessary.
BMP Checklist:
- Select drought-tolerant plants.
- Monitor rainfall weekly and soil moisture content weekly.
- Manage your irrigation system to maximize water use.
- Irrigate deeply, not shallowly.