How do you get your yard ready for a freeze in San Antonio?

Get the yard ready before the first cold night, not the afternoon of it. In San Antonio that means four jobs: know how to shut off and drain your sprinkler system, water the yard if it’s dry, put mulch on the beds, and have cloth ready for tender plants. The grass itself needs less than you’d think. Keep mowing at your normal height and let it go dormant on its own.

When does it freeze in San Antonio?

Sooner than most people plan for. At the San Antonio airport, the first freeze comes by Nov. 28 in half of years, and in one year out of ten it shows up as early as Nov. 7. So early November is the time to be ready.

A hard freeze is a different animal. NOAA tracks 28 degrees too, and the airport sees that by Dec. 13 in half of years. Texas A&M AgriLife adds that most Texas freezes hit between late January and February, and recommends having your protection in place from October or November through March or April.

Why does the sprinkler system come first?

Because it’s the most expensive thing in the yard to break. When water freezes, it expands. Texas A&M’s irrigation school says that force is strong enough to crack or burst pipes, valves and fittings.

The good news is that Texas systems don’t need the full northern treatment. The irrigation school’s steps for most of Texas are short:

1. Turn off the controller.
2. Turn off the system’s water supply at the shutoff near the meter or the backflow preventer.
3. Insulate any PVC pipe that sits above ground.
4. Drain the parts that sit above ground, like the backflow preventer.

The school also says the “blow out” method used up north is for places where the ground freezes down to the pipes, and that most Texas systems are not designed for a blow out. Skip it.

Find your shutoff now, while it’s warm. SAWS says the backflow preventer is usually in a rectangular box in the ground near your water meter, and you shut it off by turning one or both levers a quarter turn.

While you’re out there, unhook your hoses and cover the outdoor faucets. AgriLife lists both on its before-a-freeze list.

Should you water before a freeze?

Yes, if the ground is dry. AgriLife’s horticulture team says watering thoroughly is always the first step. In their words, well-watered plants survive freezes better than drought-stressed ones, because moist soil freezes more slowly and insulates the roots.

SAWS drought rules can keep your sprinklers to your assigned watering day, and the cold night won’t always line up with it. A hand-held hose is allowed any time, so you can soak dry beds and young plants ahead of the freeze. Our SAWS watering guide has the current rules.

How do you protect plants from a freeze?

Mulch first. AgriLife recommends 2 to 3 inches of organic mulch to protect plant roots. Shredded leaves count. If your oaks are dropping now, run the mower over them and move them into the beds. Our guide on raking or mowing leaves covers how.

Then cover the tender plants. SAWS says to drape plants and shrubs with bed sheets, blankets, burlap or newspaper and to move potted plants somewhere sheltered. Small, low plants can get a little “volcano” of mulch or leaves over them.

Don’t use plastic. SAWS says it doesn’t insulate or breathe well and can trap moisture. And take the covers off once it warms up. AgriLife says to remove them when temperatures rise above freezing to prevent overheating.

For citrus and other plants that really hate cold, AgriLife suggests a trick: put old-style holiday lights under the frost cloth for a little heat, and keep the bulbs from touching the cloth so nothing catches fire.

What about the grass?

Leave it alone more than you’d expect. Don’t cut it short for winter. We explain why in should you cut your grass short before winter.

St. Augustine is the grass to watch. AgriLife ranks it among the warm-season grasses with the least cold tolerance, while zoysia and buffalo grass handle cold better. AgriLife also says winterkill of the more sensitive grasses starts in the mid 20s, and that how long the cold lasts matters as much as how low it goes.

Stress makes it worse. AgriLife lists shade, foot traffic, poor drainage, north-facing slopes and packed soil as things that put grass at greater risk. A shady front yard under a live oak is exactly that spot.

How hard do freezes hit San Antonio?

AgriLife describes South Texas freezes as short but sharp drops, and says that even here, homeowners should plan for the rare deep freeze. It also warns that pipe wrap and heat tape often sell out once a freeze warning is issued. Buy what you need before the first one.

After a freeze, a brown St. Augustine lawn is normal. It’s dormant, not dead, and AgriLife says real freeze damage can take weeks to show. Don’t rush to prune either. AgriLife says to leave the dead growth on perennials and many woody plants until late winter or early spring, because cutting too early can cause freeze damage.

Then check the sprinklers before you turn them back on. SAWS says to look for leaking pipes and valves and mark them, and to reprogram the controller, since a power outage can reset it to factory settings.

What to do this week

1. Find your sprinkler shutoff and backflow box, and make sure the levers turn.
2. Buy frost cloth, pipe wrap and faucet covers before the stores run out.
3. Spread 2 to 3 inches of mulch or mowed leaves in the beds. Rather not? We do leaf cleanups and mulch.
4. Pick a sheltered spot for your potted plants.
5. Keep mowing at your normal height while the grass is still growing.
6. When the first freeze shows up in the forecast, water the dry spots by hand, shut off and drain the system, and cover the tender plants.

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