St. Augustine Grass Won’t Grow? Here’s How to Fix It


St. Augustine grass is one of the most popular warm-climate grasses in the country, and it’s found in yards throughout Florida, California, Texas, and much of the Southeastern United States. Homeowners love its large blades and rich, dark blue-green color. It’s an adaptable turf grass that can thrive in a range of soil types, and it’s easy to start from sod, plugs, or sprigs.

But, like any other turf grass, St. Augustine grass can have its issues. It needs frequent watering in order to grow, which can be a pain during times of drought. A regular fertilization schedule can also help the grass to thrive. St. Augustine grass is also prone to common problems, such as chinch bugs, grubs, brown patch, take-all patch, and gray leaf spot.

Water and Fertilize

If your grass isn’t growing well, over- or under-watering may be the culprit. St. Augustine grass needs to be watered every three to six days, so if it hasn’t been getting enough water, give it more. Hopefully, you didn’t try to mow the grass during its dormancy in the winter; St. Augustine grass spreads through both stolons and rhizomes, so cutting dormant St. Augustine grass can inhibit its growth once the warm season rolls around again.

In any case, start watering your St. Augustine grass early in the morning once or twice a week; natural rainfall can account for some of the turf’s water needs, so don’t water if it’s rained in the past few days, if you expect it to rain very soon. Watering early in the morning gives the grass time to dry out, and prevents fungal diseases. Give the grass one to one-and-a-quarter inches of water each week, enough to penetrate the soil to a depth of about eight inches. You can check to make sure water is penetrating the soil by pushing a screw driver into the lawn. It should slide in easily; if it doesn’t, the soil is too dry.

Regular fertilization can also help perk up your distressed St. Augustine grass. If you haven’t had the soil tested in the last two or three years, do a soil test to determine what nutrients your soil needs, and purchase a granular fertilizer that possesses those nutrients. You can spread it with a rotary spreader or a drop spreader, depending on the size of your lawn. Fertilize for the first time about three weeks after the grass starts growing again in spring. Use about one pound of nitrogen-rich fertilizer per 1,000 square feet. You can fertilize again in June, with about half as much fertilizer.

Check for Grubs and Chinch Bugs

If your grass is getting enough water and fertilizer and still has dead patches, it could be a pest or disease problem. Grubs and chinch bugs are the two most common pests that kill St. Augustine grass. Chinch bugs suck fluid out of the leaves, and are more common in areas exposed to full sun. Grubs feed on the grass’s roots. You’ll probably need to call on a Jacksonville lawn care service in order to deal with either insect, but you can diagnose the problem yourself. Grubs are easy to spot by pulling up a small clump of grass in the affected area and looking for small white worms in the soil or roots. To spot chinch bugs, cut the bottom out of a tin can or coffee can, press it into the lawn, and fill it with water; the bugs will float to the surface.

Look for Fungal Disease

If you don’t find any bugs in your grass, you’re probably dealing with a fungal disease, like brown patch, gray leaf spot, or take-all patch. Brown patch causes a vaguely-circular patch with dead grass in the middle and a yellow band around the outside. Take-all patch causes similar symptoms. While take-all patch causes grass roots to rot, so that stolons and stems can be easily pulled, brown patch causes leaves to rot at the base, so that blades can be plucked off and will look and smell rotten. Gray leaf spot causes gray or yellow-colored spots on blades, stolons, and sheaths. These lesions will sometimes have a darker, rotted border. Large patches of the lawn may turn yellow.

Fungicides can be applied to the lawn to treat fungal infections. Fungal infections are often chronic and may take prolonged treatment to correct. You’ll probably need the help of a lawn care specialist. The good news is well-established lawns are likely to survive fungal infections.

If your St. Augustine grass isn’t growing, you may need to overhaul your watering and fertilization schedule, or check the lawn for fungal diseases or bugs. With the right maintenance, your grass will become stronger and better able to resist the depredations of fungal diseases and bugs.

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