How to Use Frost Blankets to Protect Plants in Winter

If you live in a region with distinct seasons, you have likely developed strategies to protect plants from cold weather. However, in areas increasingly affected by unpredictable winter cold due to climate change, many gardeners now find themselves improvising. Whether you are experienced with winterizing an outdoor garden or just getting started, keeping a frost blanket on hand makes a practical difference.

Frost blankets come in many forms. Commercial options work well, but plenty of effective materials exist beyond products specifically labeled as frost blankets. When you understand how different materials function, you can respond quickly when temperatures drop and adjust easily when conditions warm again, all while protecting your plants.

Frost protection becomes essential in regions where winter conditions are severe. In Texas, for example, temperatures have recently shifted by as much as 30°F (−1°C) within a single hour. Rapid changes like this place significant stress on plants. With the right frost blanket, it is possible to buffer those extremes and keep plants healthy.

Now that your plants are well watered ahead of a freeze, it is time to explore frost blankets in their various forms and functions. Understanding the options available will help you choose the best solution for your garden and climate.

Epic GardenBox Frost Cover

Epic GardenBox Frost Cover

It’s a common factor when gardening, but now it’s easy to manage with our Epic GardenBox Frost Cover, giving you more time to start seeds, harvest, and prepare perennials for hard freezes. This set of 2 arches, made of zinc-coated steel, holds up the form-shaped frost cover. The hoops and cover are designed to fit perfectly on top of our GardenBox raised bed.

Buy at Epic Gardening Shop

What Is a Frost Blanket?

A frost blanket is a sheet of fabric, plastic, or another material used to cover plants during cold weather. Several types of frost blankets exist. Some protect agricultural crops, while others suit home gardens. Some are lightweight, while others provide heavier insulation. Certain options are commercially produced and purpose-built, while others are made from materials already found around the home.

Frost blankets protect tender leaves and stems from cold damage so plants can survive winter conditions and occasional snow. They are sometimes called floating row covers, but the two are not the same. The difference between frost blankets and floating row covers matters, so this guide includes a dedicated section explaining how they differ and when to use each one.

How Frost Blankets Work

Frost blankets work differently depending on where you place them. When shopping online for a commercial frost blanket, you will find options designed for both in-ground gardens and raised beds. Understanding the differences between these setups helps you choose the most effective frost protection for your space.

In-Ground

The ground stays warmer than the surrounding air because water molecules in the soil absorb and retain heat even as air temperatures drop. Despite this natural insulation, plants grown in the ground can still suffer cold damage when exposed to freezing conditions. For effective frost protection, use a barrier that shields plants without resting directly on the foliage.

Raised Beds

Raised beds tend to stay warmer and thaw faster during a freeze. They also make it easier to build a row cover system tailored to the bed itself. While raised beds offer some built-in protection, longer freezes still increase the risk of plant damage. Properly covering plants remains essential.

If your plants are short enough to sit below the top edge of the raised bed, a simple sheet or blanket secured over the bed often provides adequate protection. For taller plants, a raised bed hoop house works well. You can use the existing framework to support frost blankets and keep plant foliage from coming into direct contact with the covering material.

A Word On Supports

No matter which type of frost blanket you use, you need some form of support to keep the material off plant leaves and crops. When the covering sits above the plants, it traps light and warmth, allowing heat from the soil to circulate and raise temperatures beneath the blanket.

In direct sun, temperatures under a frost blanket can rise 30 to 50°F (−1 to 10°C) above outdoor conditions. Plastic coverings sit at the higher end of that range. If crops under a frost blanket reach 50°F (10°C) and the foliage touches greenhouse plastic or even a bedsheet, the plants can scorch. Subjecting plants to this stress after a cold event puts unnecessary strain on them.

To insulate individual plants, a critter cage offers a simple solution. Cover it with a frost blanket designed for pest protection, and you shield plants from herbivores while keeping temperatures about 10°F (6°C) warmer.

Larger growing areas require more creative support systems. If your frost blanket does not include built-in supports, make your own. Bamboo stakes work well, as do PVC pipes shaped into hoops for a simple hoop house. Tree branches, sticks, wooden stakes, or dowel rods also work. Any structure that keeps fabric or plastic off plant surfaces helps.

Supports also lift frost blankets above the soil, trapping heat and moisture underneath. Strong, stable frames protect plants during extended cold periods, and hoop houses or framed covers work especially well in regions that experience prolonged winter freezes.

Frost Blanket Types

As discussed, there are many options when it comes to frost blankets. Commercial frost blankets are designed to trap heat efficiently and protect plants without the extra effort required by homemade solutions. However, for many gardeners, using a simple blanket or sheet to cover plants can be an effective and virtually free alternative.

Commercial Frost Blankets

Commercial frost blankets are typically made from woven polypropylene fabric in varying weights and are designed to protect plants from snow and ice. Lighter-weight versions often serve as early spring row covers to guard against light or late frosts. Gardeners also use them to block insects and birds from young crops as plants establish early in the season.

Heavier frost blankets are not suitable for these purposes, as they restrict too much light and airflow, which can stress plants. Lightweight options work best for brief cold snaps or short winter storms.

Some commercial frost blankets feature an open-weave cloth, while others use plasticized materials. Plastic frost blankets trap significantly more heat than fabric options. Remove these covers once the sun rises and temperatures increase to prevent overheating and damage to plants.

Bed Sheets and Blankets

The downside of commercial frost blankets is cost, and online orders do not always arrive in time. If commercial options are unavailable due to budget or timing, fabric bed sheets and blankets work as effective substitutes. They provide the core benefits of a frost blanket by protecting plants from frost, trapping heat from sunlight, and helping soil retain moisture.

Sheets and blankets are less permeable than lightweight commercial frost blankets, but they also trap less heat than plastic. Drape them over supports so the material does not rest directly on your plants. Even though they retain less heat than plastic covers, remove them once temperatures rise to avoid stress. Keep in mind that heavier fabrics can block sunlight, so prolonged coverage may limit photosynthesis if left in place too long.

Canvas

Canvas is another option to consider. If you have a roll of canvas on hand for painting or use as a drop cloth, you can repurpose it for frost protection. While canvas can work in a pinch, it does not offer as much insulation as a commercial frost blanket or a tightly woven sheet. The looser weave allows more cold air to pass through.

Even so, canvas provides basic protection when you need a quick solution. Because it is permeable, remove it once daylight breaks and temperatures rise. Keep in mind that canvas becomes very heavy when wet and blocks nearly all light, so leaving it in place for extended periods can stress plants.

Tarps

Tarps can protect plants from frost, but they work best as a short-term solution. For extended cold periods, choose another material. Tarps are not designed for frost protection and can transfer freezing temperatures directly to plant tissue. Plants covered only with a tarp receive less insulation than those protected with a frost blanket or even a standard fabric cover.

Tarps work better as a supplemental layer. You can place them over fabric frost blankets to shed snow and rain. This prevents melting snow from soaking the fabric cover and transferring cold moisture to your plants. Use tarps to support homemade frost protection rather than relying on them alone.

Greenhouse Plastic

Any greenhouse plastic works especially well because it is designed to withstand direct sunlight, heat, and frost. Unlike tarps, greenhouse plastic protects plants while trapping light needed to keep them healthy through long winters. It is particularly effective when used with hoop houses. You can find greenhouse plastic at tractor supply stores, garden centers, and large home improvement retailers. Some options come as kits you can install ahead of winter, while others are sold as single sheets that you cut to size.

Growers accustomed to harsh conditions recognize how effective this material can be. One important consideration is heat buildup under the plastic. Greenhouse plastic traps significantly more warmth when exposed to sunlight, often pushing temperatures toward the upper end of the safe range. Manage removal carefully as conditions warm. When used thoughtfully, greenhouse plastic is easy to install, simple to manage, and extremely reliable for frost protection.

Floating Row Covers

A floating row cover is a frame fitted with a frost blanket that you can remove and replace as needed throughout colder seasons. This may be a simple garden frame, hoops placed over a raised bed, or a structure covered with frost cloth or plastic. The same rules apply as with other frost protection methods. Too much trapped heat stresses plants, so remove the cover as soon as temperatures rise.

When using fabric floating covers, lighter materials work best. In small gardens, heavy protection can be unnecessary and cumbersome. Dense fabric or plastic can stress plants and make the cover difficult to handle. If you plan to purchase a floating row cover, measure your growing area carefully in advance.

You can also build your own. Hoops are easy to make, quick to assemble, and simple to reuse. Wooden frames may be too heavy for some gardeners, but for row crops, a sturdier frame can be practical and effective. With adequate help, heavier structures can hold warmth around plants and provide reliable protection during extended cold periods.

Miscellaneous Frost Blankets

Some materials have unexpected uses as frost blankets. Acrylic batting tied between trees offers an easy, low-cost solution when you need quick protection. If you measure the distance between trees, you can buy acrylic fabric cut to size with a little extra to fully cover plants for a short period. The batting traps warm air and works as an effective frost blanket without the need for stakes, since the trees provide support.

Acrylic fabric may be too heavy for mild early spring frosts, when temperatures are not low enough to require tightly sealed coverage.

Plankets and similar frost bags are a newer option for protecting plants during cold weather. These covers are designed to trap warm air and shield plants from frost damage. Most include a built-in cinch cord that makes them easy to secure around a plant or frame.

Plankets work especially well for container-grown plants. They install and remove easily, and the fabric is lightweight and breathable. If you want a ready-made fabric solution for protecting crops from freezing conditions, this is a reliable option.

Frequently Asked Questions