By Bob Dailey
Most of us in The Woodlands have St. Augustine turf grass. It is, by far, the most shade tolerant of all the warm-season grasses. However, many residents notice their St. Augustine thinning under trees. Here’s the probable reason. When the area was sodded, the tree canopy above it was less dense. Therefore, even though it was planted in shade, it received more filtered sunlight. As the tree canopy grew denser, the grass received less filtered light.
The solution: Lightly prune the tree to allow more light to penetrate through the foliage. Keeping foot traffic to a minimum and setting the mower to its highest level will also help. If all these fail, try replacing the sod with a shade-loving groundcover such as Mondo grass, liriope, Asian jasmine, English ivy or ferns.
In southeast Texas, rains in May generally provide enough water for turf grass. St. Augustine needs only ½ -1 inch per week to stay healthy. Don’t overwater. Overwatering can cause fungal infections. Check your irrigation controller and your sprinkler heads to make sure they are operating properly. Make sure you set it accurately to comply with the two-day-per-week Odd/Even Defined Irrigation Schedule.
New sod and patching bare spots
There is still time to put in new sod or fill in some bare spots. Woodlands Water offers variances from the Defined Irrigation Schedule to ensure new turf is adequately irrigated. However, be very careful that the area doesn’t become a swamp. Too much water is just as bad as too little. It’s also not too late to add compost or peat moss to yellowing patches of grass.
Establishing deep, dense lawns
Taller grass blades accomplish several things. First, they keep the ground cooler than the ambient temperature. They help hold in moisture…which means you need to water less. Weed seeds need sunlight to germinate. Taller grass blades shade the ground and discourage weed growth. Thus, don’t be afraid to set your mower height to the highest setting. Avoid scalping. Crew cutting St. Augustine or any other grass will shorten its life span and make them more vulnerable to insect damage and disease.
If you haven’t yet fertilized, you can do so now. Do not use “weed and feed” products. Instead, use a slow-release fertilizer with a 3-1-2, 4-1-2 or 6-2-4 ratio. These three numbers represent the percentage of nitrogen, phosphorus and potassium in the fertilizer. Instead of bagging grass clippings, use a mulching lawn mower. The grass clippings are high in nutrients and will help fertilize your lawn.