Without sufficient water and fertilizer, many turf grasses go dormant within the hottest months of the year. Warm-season grasses, however, encounter their peak growth in warm weather, and it does not take much to restore their green color. Extra water and some nitrogen fertilizer will give the lawn a fast increase, and continuing maintenance helps keep the lawn from turning brown again.
Sulfur and water needs are similar for many warm-season grasses, but perfect mowing height varies by species. Reducing grass at the correct height, and only removing one-third of the entire height every time you mow, helps keep the lawn healthy so it’s more likely to produce lush green growth. St. Augustine grass (Stenotaphrum secundatum), hardy in U.S. Department of Agriculture plant hardiness zones 8 through 10, should be mowed between 2 and 4 inches high. Zoysiagrass (Zoysia spp, USDA zones 6 through 9) will best when mowed between 3/4 and 2 inches high. Bermudagrass (Cynodon spp, USDA zones 7 through 10) should be mowed between 3/4 and 1 1/2 inches high. Mowing in the higher end of the leading range increases drought tolerance. Bermudagrass has invasive trends in some places.
Nitrogen is the key nutrient for supporting fast, lush lawn growth to quickly turn a brownish lawn green. Application prices are determined by the amount of actual nitrogen in the fertilizers and varies by manufacturer. You can see how much nitrogen is at a fertilizer by checking the N-P-K ratio to the fertilizer package. The first number in this ratio lets you know what percentage, by weight, of the sulfur is sulfur. To continue to keep lawns green and growing, apply 1/2 to 1 pound of actual nitrogen per 1,000 square foot every four to eight weeks. Higher, more regular nitrogen applications keep the lawn producing new, green growth. For St. Augustine grass, then make sure you use slow-release fertilizer to deter insects.
Even by itself, additional water may restore color to a brown lawn. When you’re employing high rates of nitrogen too, it becomes much more important to water regularly. Water moves that the nutrients into the soil so that they may be used by plants and also helps dilute nitrogen fertilizers to prevent burn the lawns. As a rule of thumb, apply 1 to 1 1/4 inches of water every week to bermudagrass and zoysiagrass, and one inch of water into St. Augustine grass. This should keep the lawn from going dormant, yet to keep the grass lush and green, you might need to water around 2 1/2 inches each week in very warm weather.
To conserve water, then you may decide to only keep the observable front yard green within the summer and let the remainder of the lawn go dormant. A dormant lawn will start growing again when the weather cools or it starts to rain, even though drought conditions might thin the lawn by splitting some grass plants. Alternately, you may choose to water only when the lawn shows signs of drought stress or the soil is getting hard and dry. This is going to keep the grass more green than brown but won’t result in a thick green lawn. If you choose to water less, make certain you also cut back on fertilizer applications since the bud won’t be growing rapidly enough to require the nutrients.