By Stephen Brueggerhoff, CEA-Horticulture, Galveston County AgriLife Extension
Keeping up with lawn appearances can have its challenges in the heat of a good old Gulf Coast summer. Plentiful seasonal spring rains are just a memory now, and our efforts should be focused on home turf maintenance practices that are based on science and a little bit of common sense.
Let’s talk St. Augustinegrass, the grass of choice for home yards and appropriate for our region. St. Augustinegrass is a warm season grass, and warm season grasses typically undergo seasonal summer stress from environmental factors such as temperature and water; too high for the former, and oftentimes too little for the latter. While we cannot control the temperature, we can control the amount of water we apply to our lawns.
The challenge determining an appropriate watering rate is specific to the site itself. Former AgriLife Turfgrass Specialist Dr. Becky Grubbs explains “Making a recommendation on water is difficult because it varies so much with location, grass species and ever-changing environmental conditions.” AgriLife Extension offers an online application called Water My Yard (https://watermyyard.org), a science-based tool that helps take the guesswork out of when and how much to water. Advice offered is calculated from real-time data collected from a network of local weather stations, rain gauges and plant biology. You can also download an app to your mobile device for ease of use. Once at the website, you create a personalized account and set up your irrigation profile that includes the type of irrigation used (oscillating, in-ground spray, drip). Then based on your location, experts send customized weekly water application advice to your email. My most recent experience using the app: my area is known to receive a precipitation rate of 0.3-inches/hour. Watering recommendation for April 22 to April 28, 2023 (Saturday through Friday) is 0.27-inches of water needed, estimated at one watering for 53 minutes.
Remember my commonsense comment? It’s always best to visually inspect your lawn for initial signs of water-related stress prior to automatically watering. A simple method for checking on water-related stress is to walk across your lawn and look for a reduced leaf bounce-back; grass leaves don’t immediately bounce-back, and your steps leave an indention. Time to water on! We do use a general statement for watering one to two times per week for a 1 to 2-inch total application during hot and dry weather. However, it is prudent to use technology and data to avoid overwatering.
Warm season grasses are focusing energy for growth in the cooler seasons of spring and fall. While they are not truly dormant in summer, performance and root growth is not as vigorous. Because of this kind of biological activity, fertilization for grasses should be applied once in the spring and once in the fall. A good rule of thumb for scheduling spring fertilizer application is an estimated 4 to 6 weeks after the last frost date, and for fall 4 to 6 weeks prior to the first frost date. Like most plants, grasses utilize a number of available nutrients in the soil for growth, and nitrogen is the nutrient required in the highest quantity. Fertilizer application ratios are dependant on soil nutrient availability and my recommendation is to commit a soil test to determine if there are any potential nutrient deficiencies. Urban soil tests are administered for a small fee from the Texas A&M AgriLife Extension Soil, Water and Forage Testing Laboratory in College Station. Forms and fees can be found online: soiltesting.tamu.edu. You will receive a report with recommended landscape application rates and based on said deficiencies. The general formula for the amount of fertilizer to apply annually is 1-pound of the percentage of nitrogen in the product per 1,000 square feet. Example: a bag of fertilizer has a 21-0-0 ratio (21 percent nitrogen.) Divide 1-pound by 21-percent to apply 4.75 pounds of product per 1,000 square feet. Don’t forget to measure the square footage of your lawn to put advice into action.
My last bit of advice is to avoid products containing a combination of herbicide and fertilizer. Pre-emergent herbicides and fertilizer should be applied individually and specific to a research-based deficiency or need rather than as a preventative in the home landscape. The best method of weed control is encouraging optimal lawn health. I invite you to share your ideas and successes in your garden by browsing online to my Facebook webpage: facebook.com/stephenbhorticulturist, as well as keeping up with programs and activities promoted from Galveston County AgriLife Extension. Lawn on, my fellow residents and I’ll see you in the garden.
