5 ways Your Austin, Texas Garden Survives the Freeze

“Will my plants survive?” and “What should I do to keep them alive?” are questions I get a lot from my clients.

I hate to be unhelpful, but often the answer is, “it depends.”

We all know that this is how Texas winters go - it's late summer, then it's winter for a night. Or three. Then it's fall. Then spring, then winter again for a couple days. Ahhh, the joys of being wedged between a warm Gulf and the flat, windy American plains.

While you are cozy indoors watching the mercury drop, you might wonder which plants will make it through to the other side of this crazy winter moment. Here are 5 factors that affect whether they do:

1) Variety.

Generally, your garden plants can be broken into two categories; warm-season and cool-season. Warm-season plants generally cannot tolerate any type of frost (32 degrees). These include your tomatoes, basil, peppers, cucumbers and more. Most cool-season plants are frost-tolerant, but this also depends on the variety. Some plant can deal with a light frost (30-32 degrees for a couple hours), which includes your lettuces, while others are super toughies. The more cold tolerant varieties include certain spinaches, most root crops (carrots, radish, beets, turnips), and cole crops ( such as broccoli, collard greens, cauliflower and kale). Get to know your variety and what it can take, and this will determine it’s love of the winter snap. Not only that, but some varieties of the same species (different types of broccoli for example), make for better candidates for planting in Texas. I have a plant guide here you can order that tells you specific varieties of veg that you should try to plant.

2) Protection.

The two ways your plants need protection is from the wind and on their roots. So I recommend 1) use mulch, and/or 2) use a light blanket or row cover. A row cover can be as simple as a light bed sheet weighted down with stones. You can also find a product in stores or online called frost fabric, frost blanket, row cover, or something similar. Trying to order or buy this a few days before a predicted hard freeze is a bad idea. If you didn’t get your cover early in the season, a blanket will do. It should cover the top of the plants and drape to the soil. The idea is that the soil is warmer than the air and this warmth will be trapped around your plants. It also protects from chilly winds. This can lower the temps around your plant up to about 10 degrees that will make the difference between survival or death.

3) Weather.

The wind chill, the temperature and the duration of said wind and temps will make a huge difference. Remember when we said in #1 above that some varieties are happy at different temps? This is due to the water content in their cells, the rigidity of their cells and other factors (which are based on DNA). A 31 degree two-hour span in the middle of the night is entirely different than 12 hours below freezing that reach down into the low 20s. It’s often impossible to know exactly what Tonight’s Freeze will look like until we’re in it, so the best we can do is plant the right plant at the right time of year (see #1 above) and use protection (#2 above).

4) Watering.

The soil will always be warmer than the air, sometimes by 20 degrees or more. The good news about our finicky weather is that it normally doesn’t stay cold for too long. When you see a freeze in the forecast, be sure you water your garden thoroughly. When the air freezes the moisture on the surfaces of your plants, if your plants are able to absorb nice cozy liquid water from their roots, they will be much happier and stronger against the temporary cold. Also, a very dry plant is a stressed plant, and any type of stress weakens their immunity and structure strength to recover from extreme temps. You want a plant to be strong enough to shed some leaves or drop a branch and still survive. Soaked feet before the freeze can help this.

5) Maturity.

Finally, the age of your plants can determine their post-freeze outcome. Remember the soil is warmer than the air. Also, the deeper the soil, the warmer it is. The deeper your plant roots go into the soil, the more of their roots will be unaffected by the air temps. The longer the branches, the more leaf coverage, all affect their cold hardiness. So of course, the older the plant, the deeper the roots, the more branches and leaf surface. The more recently you transplanted, the more tender they will be. Since there’s no real way to predict when our first freeze or hard freeze will be, it’s best to start planting your Texas winter garden in early fall and contunue to plant, harvest, sow, harvest and plant some more every few weeks.

It can be annoying not to know, but that’s kind of how gardening is. You do some things, you make good choices, and you hope for the best while nature and weather does it’s thing. The absolute #1 thing we can do as gardeners is to get your plant in the ground during the right month of the year. To help you make that good choice, I’ve created a month-by-month guide on what to plant, how to tend and harvest your central Texas garden. You can purchase that guide below.