9 Smart Ways to Protect Your Tender Crops From Frost

Just because cold weather is coming doesn’t mean you must allow your crops to succumb to the first frost. Most are nearing the end of their productive cycle but you can keep them going just a little longer because, while the nights may occasionally dip below freezing, there are still some warm days ahead. 

Look up the average first frost date for your region. As that date gets close, keep an eye on the weather forecast. Anytime there’s a frost advisory or you see an overnight low predicted to be 36°F (2°C) or lower, it’s time to take action. Weather forecasts aren’t always right, and there are many microclimates within any given area, so give yourself a few degrees of extra cushion “just in case.”

Bring Plants Indoors

Do you have frost-sensitive crops or ornamentals in pots or containers that need to be protected? If so, bring them in for those overnight cold snaps. Container gardening offers a lot of advantages, including having a highly portable garden! 

Move your potted plants into a protected garage, shed, or indoor space anytime the weather threatens frost. During the day, when the sun comes out and the temperatures warm, bring them back out again so they continue getting enough light. 

Moving your tender crops back and forth between the garage and the garden will work for a while, but consider it a temporary solution. Eventually, most of your summer crops will stop producing, weaken, and die. Taking them in for the first few fall frosts allows you to extend the growing season as long as the fall days are still relatively warm. 

Install Floating Row Covers

Floating row covers are a simple yet extremely useful invention. A floating row cover is a sheet of thin, lightweight fabric used to cover low-growing plants. Rather than protecting a single plant, floating row covers extend over your entire garden bed, including raised beds!

Use these sheet-like covers to help retain some heat around your beds, protect your crops from light frosts, and ultimately extend the growing season. If you live in a climate with mild winters, cover your cool-season crops with floating row covers to keep them going all winter. They also protect your crops from insect pests.

You can use floating row covers by simply draping them over the foliage and weighing down the edges so they won’t blow away. You can also use hoop supports over your crops and drape the covers over these for a more greenhouse-like effect that fully supports and suspends the cover without touching the leaves.

Most floating row covers allow enough sunlight, airflow, and water through so you can leave them in place for days or weeks at a time. If they get weighed down with falling leaves, rain, or snow, just shake them off and re-set them over your plants again.

Use Cloth Covers

When there’s a frost warning, and you don’t already have floating row covers, drape a lightweight blanket, sheet, or towel over your crops. Because of the weight of these fabrics, you’ll probably want to support them with something so they aren’t resting directly on the leaves with the risk of flattening or breaking them. 

Any evening when cold temperatures are predicted, protect your tender crops with cloth covers. This will insulate them and keep them from freezing during light frosts.

Since sheets and towels are relatively heavy, they won’t allow enough sunlight and air circulation that your plants need, so you’ll need to remove them each morning when the air warms above freezing. This handy trick is only useful in a pinch and can extend your growing season by a few weeks, but only if you cover your plants each night before a freeze warning.

Cover With Cloches

When you’re trying to protect a few special small plants, especially when you’ve just planted tender seedlings out in the spring, cloches are the perfect protection from light frosts. A cloche is a domed cover used to protect from insect pests, digging squirrels, and frosts. They may be made of wire mesh, plastic, or fabric. You’ll need an enclosed plastic or fabric cloche cover to protect your plants from frost. 

One nice thing about using cloches is that most can be left in place for extended periods. You won’t need to remove them and re-install them every day like when you cover your with sheets and towels. 

The primary limiting factor with a cloche is to make sure your plant fits under it. If you’re using cloches in the spring to protect crops from early-season frosts, nibbling mammals, or hungry insect pests, you’ll need to remove them when your plants outgrow their allotted space.

Protect With Overturned Pots

Do you have small crops you’d like to protect from an occasional frost? You don’t need anything fancier than an overturned pot. Use a large, plastic nursery pot as a temporary cover. Plastic buckets and plastic storage bins also work great. Do you have gallon-sized water jugs or two-liter plastic bottles? Cut off the bottoms of these plastic bottles and place the tops over smaller plants; they’re just the right size to cover seedlings.

While plastic crates and baskets may be large enough to cover your beds, they won’t work if they can’t offer a solid protective layer. Any item with large holes or gaps won’t protect from frost unless you cover it with something else, like a towel or blanket. Cardboard boxes over your plants also work in a pinch. 

Putting a bunch of upside-down pots and buckets and boxes in your garden may not look really attractive, but let’s be honest, if they protect your tender plants from frost, they’ve done their job well. You also really only need to cover overnight, and you’ll remove the covers again in the morning. If your days stay at or below freezing, an overturned pot or blanket won’t be of much use anymore. 

Build a Cold Frame

If you’re really serious about protecting your tender crops from frost, build or install a cold frame. A cold frame is a structure that generally encloses multiple plants and acts like a miniature greenhouse. This enclosed frame traps heat during the day, keeping the air warm and retaining some of that heat during the night to prevent freezing. 

On warm days and rainy days, open the top of the cold frame to allow airflow and access to water. Then, close the cold frame again overnight to trap the heat within. Cold frames are compact and versatile. You can buy them as a kit or if you enjoy DIY projects, build your own. In mild climates, you can easily grow cool-season crops through the winter in a cold frame, and use it to extend the longevity and productivity of any frost-sensitive crops.

Use a cold frame to extend your gardening season earlier in the spring and later in the fall. In some climates, you can use a cold frame to grow herbs and vegetables right through the winter. Cool-season vegetables are the perfect cold frame crops. Use these handy structures over a single bed, over several beds, or in your raised bed garden!

Insulate With Water

Water has some surprising insulation qualities that you can use to your advantage. Here are a few tricks you can try:

Water Trick #1: A couple of days before an anticipated frost, water your plants. Water them enough to make the soil moist without being saturated. The moist soil will absorb enough heat during the day to release it at night and essentially insulate your crops from the cold. You’ll still want to cover the plant with something so the top doesn’t freeze.

Water Trick #2: Set out a couple of gallon jugs filled with water in your garden. They will warm in the sun during the day. At night, when a frost threatens, cover your tender plants along with the sun-warmed water jugs. When the temperature drops at night, the jugs won’t cool as quickly as the surrounding air. When covered alongside your plants, they’ll moderate the temperature under the coverings to keep it slightly warmer than the surrounding outside air.

Apply Mulch

Mulch is a great way to help protect the roots of your plant. It won’t do much to protect the foliage from frost, but if you’re hoping to keep your plants healthy for as long as possible, take care to protect as much of the plant as possible. 

A three-inch layer of mulch around the roots has more benefits than keeping the roots warm. Mulch also keeps your plant’s roots moist and suppresses weeds so you’ll save time and energy not focused on pesky weeds. 

At the end of the growing season, it’s handy to mulch your garden beds anyway. You’ll get a head start by mulching your fall plants before winter. Winter mulch reduces soil erosion due to wind and water. It also helps regulate the soil temperature to prevent frost heave and can even help enrich your soil with minimal effort. 

Take Cuttings

Want to keep some of your garden herbs going through the winter? Take stem cuttings. You can easily propagate basil with a few cuttings and keep it going in your kitchen window during the winter.

Try taking cuttings of mint, hyssop, rosemary, sage, oregano, and thyme. These plants are all fun and easy to propagate. You can keep them going indoors in a sunny window during the winter and plant them out again in the spring. Overwintering cuttings is just another way to enjoy gardening year-round!

Frequently Asked Questions