Colder Weather Dampens Need to Irrigate Lawns

Most lawns in The Woodlands consist of St. Augustine grass – a warm-season grass that goes dormant in the fall and winter. The grass starts to turn a little yellow and the intuitive thing to do is to add more water. In fact, irrigation during the fall and winter has the potential to do more harm than good.

In colder months, therefore, St. Augustine requires little or no watering. Soil-borne diseases, such as take-all patch, brown patch and others generally take hold in overwatered lawns during the winter, although the damage is not usually seen until late spring or summer. Additionally, dollar weed and sedges thrive in wet soil during winter, only to create an unsightly mess when they emerge in the spring.

Here are some guidelines that residents can use to assure strong healthy lawns:


Beginning in October through March, add no or very little water to your lawn. St. Augustine is dormant during the fall and winter. Begin watering every two weeks in April. From May to September, water twice a week in compliance with the Defined Irrigation Schedule now in effect.


Set mower heights to the highest setting. Mow only once or twice a month during the winter months. In April, mow twice, and then mow every five to seven days through September. Some residents only mow twice a month during the summer months to encourage grass to produce more food for a stronger root system.


Just before you add compost, aerate the lawn.


Add 1/2 to 3/4 inch of compost to your lawn every April and October. This will increase the organic material in your soil, promote beneficial microorganisms, and help grass grow deeper roots.


Fertilize in spring with a well-balanced fertilizer.


Best times to sod are March through June. Worst times are August and September, which are historically the hottest and the driest months. Optimal growing time for St. Augustine (and therefore the optimal time to resod) is spring through early summer.


Well- maintained St. Augustine does not need dethatching, regardless what anyone tells you. A high microbic and macrobiotic presence in good soil will solve that problem. If you feel you absolutely must dethatch, do so only from the middle of April through the middle of June. St. Augustine grass grows horizontally and has a lot of horizontal aboveground stems. These stems are necessary to the plant’s health. Many people confuse this with “thatch,” and actually do more harm than good when they “dethatch,” which actually damages horizontal stems, stresses the plants and weakens the root systems.