|Lawn water management practices during dry times depends on soil type, grass variety|
|Larry Spradlin | Hopkins County Extension Agent|
July 2, 2005 - Homeowners know how important water is to a healthy lawn. Water is a limited resource in Texas and it will become more limited as our population grows. Water rationing programs will surely be occurring if we don't receive some rain soon. Here are some tips on conserving significant amounts of water with no loss in grass quality.
Some factors include soil type and grass variety.
Soil type affects the amount of water a lawn needs. There are three soil types: clay, loam and sand. Clay soil retains the most water and thus needs watering less often. However, because water seeps into clay soils more slowly, it must be applied at lower rates over a longer period of time. Sandy soil retains less water than clay soil, but less water is needed to properly wet sandy soil. Therefore, watering sandy soil takes less time than watering clay soil but must be done more frequently. Loam soil lies between clay and sandy soil in its ability to hold water. Loam retains a moderate amount of water following irrigation and requires a moderate amount of water.
Water moves very slowly into some soil, especially fine-textured clay and loam. If a sprinkler head applies water faster than water can seep into the soil, significant water can be lost as run-off. To avoid this problem, use sprinklers with low application rates and/or irrigate to a point just before run-off. Then stop watering! Let the surface dry and then begin watering again. Repeat this process until the soil is wet to the desired depth.
Water can be lost when it leaches or filters through the soil, especially in coarse-textured sand and loam soils. Both water and nutrients may seep below the root zone where then are unavailable to plants. Watering deeper than the root zone should be avoided.
Grass species vary significantly in their water needs and drought resistance. Here is a list of grasses and their drought tolerance: Excellent - Buffalo grass; Good - Bermuda grass, Zoysia Japonica; Fair - St. Augustine grass, Centipede grass, Rye grass andTall Fescue; Poor - Zoysia Matrella and Kentucky Bluegrass.
WHEN TO WATER: Rather than watering on the same schedule each week, adjust your watering schedule according to the weather. Irrigate deeply, then wait until the grass begins to show signs of drought stress before watering again. Symptoms of drought stress include grass leaves turning a dull, bluish color, leaf blades rolling or folding, and footprints that remain in the grass after walking across the lawn. A lawn that is watered deeply should generally be able to go 5 to 8 days between waterings. Early morning is the best time to water. Wind and temperatures are usually the lowest of the day, and water pressure is generally good. This allows water to be applied evenly and with less loss from evaporation. Watering late in the evening or at night causes leaves to remain wet for an extended period of time, which increases the chance for disease. Mid-afternoon watering may cause uneven distribution from high winds.