How to Protect Plants from a Freeze

• Unless you want Jack Frost to catch you off guard, you must know how to protect plants from a freeze. Bring them inside, cover with breathable fabric, add mulch, or add a heat source.

Even lawn care experts use these proven techniques. Follow them, so your plants can survive (and thrive after) the cold winter.

1. Identify which plants need protection

Since freezing weather can do a lot of harm to plants, you must be efficient in your approach. That’s why you must know the forecast and how cold it’s going to get. There’s a difference between 30 degrees and 18 degrees — some plants can handle 30, but not 18.

Once you know how cold it’s going to be, you’ll need to identify which plants in your garden need the most help to survive the freezing temperatures. The types of plants that need extra care during the cold months include:

• Tropical and subtropicals like hibiscus, jasmine, and bougainvillea
• Tender perennials like verbena, coneflower, and iris
• New growth and young seedlings

When you buy a plant at the store, you can check the tag for the temperature the plant can withstand. Even online plant shops usually provide information about the specific plant, including its preferred temperature range.

But if you need help determining the survival rate of your existing plants, you can turn to Google. You can use the search term “cold hardiness [plant name]” without the quotes. For example, typing “cold hardiness common verbena” will yield results showing the temperature common verbena can withstand.

Another helpful tool is the USDA plant hardiness zone map, which is the standard gardeners use to determine which plants can thrive at a specific location. Using it can help you identify which cold-hardy plants pass the minimum requirements for your area.

2. Bring plants inside, if possible

Once you’ve determined which of your plants need winter protection, you can bring the ones you can inside your home — potted plants and hanging planters.

You’re bringing these plants inside your home to help keep them warm. But there’s a bonus. Apart from protecting your plants from the freeze, you’re also making your home more cozy.

My tip: Don’t try to squeeze all of them inside your living room. You also can temporarily house your plants in your garage, porch, heated room, or any protected and warm structure.

Note: Not all small plants are vulnerable to frost. According to Rhoda Burrows, professor and extension horticulture specialist at South Dakota State University, some vegetable crops like broccoli and cauliflower are frost-hardy and can tolerate moderate freezes of around 24 to 28 degrees Fahrenheit.

3. Add mulch

For plants you can’t bring indoors, give them natural insulation by adding a thick layer of mulch. However, this is not something you can instantly implement compared to just bringing the plants indoors. You must consider that mulching requires some time and effort.

Chipped bark and pine straw are good mulches you can use to protect plants from the cold. But if you’re trying to protect new growth, it would be better to use leaf mulch. This way, you’re not adding weight and pressure to the young plants.

4. Water the soil

Wet soil can hold more heat when covered with mulch. But even if you’re not planning to add mulch, it’s recommended to water the soil thoroughly 24 to 48 hours before a freeze.

Since wet or moist soil can retain heat better than dry soil, watering the soil can provide natural insulation for the roots — protecting them from frost damage.

My tip: While it’s a good idea to water the soil, avoid watering the leaves of your plants before a freeze. Water on the leaves can get frozen and cause frost damage like leaf burn and wilting.

5. Cover plants

Another quick solution to protect plants from a freeze is to cover them using a breathable fabric like blankets, sheets, towels, fleece, and tarps. Trapping the heat produced by these plants will help keep them warm. Note, though, that this is not a set-and-forget thing, as you’ll need to ensure your plants don’t get soaked or overheated.

Follow these steps to cover your plants before a freeze:

• Set up stakes to support the covering and prevent it from weighing down on your plants.
• Place the covering on top to create a tent-like structure.
• Add weights like stones and bricks to the corners to anchor the fabric and keep it from being blown away.
• If you’re expecting rain or snow, place plastic sheets on top of the covering. You can leave the plastic sheets on during the rain or snow, but don’t forget to remove them afterward to prevent overheating.

My tip: Avoid covering your plants directly with plastic, as plastic material can transfer cold to the leaves and further damage your plants.

6. Add heat with lights

This technique not only helps keep your plants warm during winter but also adds a decorative flair fit for the season.

Wrap old-school incandescent lights around your plant or tree that needs protection. The heat generated by these lights can help keep your plants comfortably warm and looking good at the same time.

During bouts of freeze, you can combine this approach with the previous tip (tip #4). Covering the lighted plants with a blanket can help trap the heat inside.

Note: Use incandescent lights instead of LED lights since you want your lighting to produce heat. Unlike incandescent lighting, LED lights only get slightly warm, if at all.

FAQ about protecting plants from freeze

How do I save my plants after a freeze?

To save your plants after a freeze, you’ll first need to assess the damage. Then, you’ll want to water and fertilize your plants. Also, prune dead branches and remove wilted flowers. For your lawn, you may want to apply pre-emergent herbicide and avoid foot traffic.

How long can I keep plants covered during a freeze?

If you’re expecting several nights of freezing temperatures, you can leave your plants covered for up to seven days. Once the temperature rises again to above 32 degrees, remove the covering, says Mark Tancig, commercial/residential horticulture agent at the University of Florida IFAS Leon County Extension.

For several days, you’ll have to cover your plants at night and remove the covering during the day.

Will a plastic bag be enough to protect plants from frost?

No. Never use a plastic bag to protect your plants from frost. If you need to protect it from precipitation, cover it with breathable fabric first then layer a plastic sheet on top, removing the plastic when the rain stops.

Use the right techniques to keep your plants safe during a freeze

These five tips can help save your plants from winter freezes. But while they’re simple to do, it’s best to leave these tasks to the experts. Contact a local lawn professional today, and let them protect your plants from a freeze while you keep warm inside. Plus, they also can help restore your lawn and landscaping after a freeze.

Main photo credit: Pxhere

Melanie Joseph

With hands-on experience in gardening and lawn care, Melanie has been a dedicated writer for LawnLove for years now. She’s passionate about sharing practical tips to help homeowners cultivate healthier, greener yards — one blade of grass at a time.

Posts by Melanie Joseph