St. Augustine After a Freeze: Is It Dead or Just Dormant?
How to tell if freeze-damaged St. Augustine is dead or dormant, why you should wait for spring, and what to do (and not do) while it recovers.
The short version
- A brown St. Augustine lawn after a freeze is usually dormant, not dead.
- Wait for spring green-up before deciding what died. Most lawns recover on their own.
- Don't fertilize, scalp, or spray weed-and-feed to "help" it. That does more harm than good.
- Replace only the areas still bare once the rest of the lawn has greened up.
Dormant vs. dead
St. Augustine goes dormant and turns tan or brown once it gets cold. That's normal, and the runners underneath stay alive. A hard freeze can kill some runners, especially in exposed spots, thin areas, and lawns that were stressed going into winter. The tricky part is that in January, dormant grass and dead grass look exactly the same.
How to check (without waiting until spring)
- Look at the runners. Scratch or cut into a runner near the soil. A firm, white or green inside is a good sign. Mushy, dark, or dried-out runners are a bad sign.
- Do a pot test. Texas A&M AgriLife suggests cutting a few small plugs of grass with roots attached, potting them, and setting them somewhere warm and sunny. If they start growing in a week or two, your lawn is dormant, not dead.
- Check several spots, including sunny, shady, and exposed areas. Damage is often uneven.
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What to do while you wait
- Be patient. Let spring green-up show you what made it. Exposed areas are the most likely to need repair.
- Water lightly only in long dry spells. A dormant lawn needs much less water.
- Pull or spot-treat weeds instead of using weed-and-feed. See winter weeds.
- Rake up dead leaves and debris so light and air reach the runners.
What not to do
- Don't fertilize to green it up. Feeding a damaged, dormant lawn mostly feeds weeds. Wait until it's actively growing. See when to fertilize in spring.
- Don't scalp it to clear the brown blades. Mow at your normal high setting once it's growing.
- Don't dethatch aggressively. Ripping at a weakened lawn can pull out the runners that are trying to recover.
Spring: repair what didn't come back
Once the rest of the lawn has fully greened up, usually by mid to late spring on the Gulf Coast, any area still brown and bare likely needs replacing. Rake out the dead material and fill it with plugs or sod. I set plugs with a soil plug tool. See how to fix bare spots. If freezes hit your yard often, a more cold-hardy variety may be worth it. See St. Augustine varieties compared.
Before the next cold snap: water the lawn a day or two ahead of a hard freeze if the soil is dry, since moist soil holds heat better. See fall and winter care.
Everything in my St. Augustine program
The fertilizers, weed killers, fungicides, and tools I actually use on my own lawn, with links to buy.