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Janet Laminack: Mow before fertilizing


The calendar may not say it’s spring yet, but we know in our hearts it is here. Weekends now awaken with the soft buzz of lawn mowers, leaf blowers and edgers. It’s time to start caring for our lawns again, and I have a few tips that will help you have a healthy lawn.

Most of our lawns in this area are either Bermuda or St. Augustine, and both are considered warm-season turfgrasses. Fertilize a warm-season grass after it has begun to actively grow, which means waiting until you have mowed the grass a couple of times. This means you have been mowing for weeks now, but it was probably only weeds. You want two mowings of the turf itself before fertilization.

Now is the time to add a layer of organic material if you like to do that. This improves soil aeration and drainage. Adding a very thin layer of compost is an excellent way to add a few nutrients to your lawn and improve the drainage of a clay soil or the water-holding capacity of a sandy soil.

The other thing you can do right now toward fertilization is take a soil test. There are many soil labs available that will analyze your soil to find what nutrients you are lacking and provide recommendations on how to improve it. You can find information on how to submit a sample to the Texas A&M AgriLife Extension Soil Lab at A routine analysis costs $10.

Cool-season weeds such as dandelions and henbit are actively growing at this time, and soon we will start seeing the warm-season weeds. Mowing regularly can prevent the weeds from developing seed heads. It’s too late for a pre-emergent herbicide (weed killer) on our warm-season weeds that will be here soon. Pre-emergents prevent weed seedlings from developing. Once you see full-grown weeds, it’s too late for the pre-emergent. If weeds are a major problem, you might consider pre-emergent applications in the future. Mark your calendar ahead of time because those dates tend to sneak by. Fall applications should happen in September, and spring dates are late February and early March.

There are post-emergent herbicides available to kill weeds that are larger and growing. However, it is best to kill them as young as possible and before they start spreading seeds. As with all chemicals, read the label carefully. Many herbicide labels say to avoid applying around or under trees, shrubs or other desirable plants because the chemical can damage or even kill these plants. And the label is the law.

Mowing is one of the most critical aspects of maintaining a healthy turfgrass. Regular mowing at the right height can keep a lawn growing densely and healthy and will cut down on weeds. The best and most safe rule of thumb is to never remove more than one-third of the leaf blade at any one time. Mowing less frequently, when the grass is taller, removes too much of the plant at one time and may even remove the growing point of the grass. Most of us don’t want to mow more frequently, but it is one of the secrets to having a dense and healthy lawn.

And finally, how should you water your lawn? Most homeowners overwater their lawns. Water when the lawn needs it and to a depth of 6 inches with each watering. In our clay soils, you may have to run your cycle a few times in one day in order to get the water down six inches without running off.

Quick, frequent watering will produce shallow root systems that don’t survive our hot summers. You can wait to water your lawn until when you see symptoms of drought stress, such as a dull bluish color and the leaf blades rolling up. Lawns that are watered deeply can go five to eight days between watering. And remember, if we’ve been receiving rain you don’t need to irrigate. Learn how to manage your irrigation control box because water is a limited resource.

We have many online publications available to help you better understand how to use water responsibly to create a beautiful landscape and green lawn. If you would like more information, give us a call at 940-349-2892 or email, or visit us online at


JANET LAMINACK is the horticulture county extension agent with Texas AgriLife Extension. She can be reached at 940-349-2883 or