Bring potted plants inside, water and mulch perennials, and cover tender landscape plants — these are the basics of how to protect your plants from a freeze.
You can also take additional steps, such as building cold frames and using Christmas lights as an extra heat source. To help discuss the best ways to protect your flowers and veggies from the cold, we’ve included insights from two experts who shared valuable tips.
If you’re not in the mood to do this yourself, book one of our landscaping pros to protect your plants from cold temperatures during fall, winter, and early spring.
| Note: Freeze events happen when temperatures drop to 32 F or below, but frost can form on plants when air temperatures are higher, in the mid-30s, depending on weather conditions. A hard freeze, or killing freeze, on the other hand, happens when temperatures drop to 28 F or below for an extended period. In any of these cases, it is important to protect your plants. Let’s discuss how. |
1. Move Container Plants Indoors
Potted plants can be especially susceptible to cold damage since they are not insulated by the ground, unlike plants grown directly in the soil. To prevent this, “containers with tender ornamental plants should be moved to a sheltered area or better yet, inside a garage at night,” advises Karen Mitchell, Extension specialist at Purdue University.
Potted annuals, warm-season vegetables, and young plants will also need to be brought inside as soon as nighttime temperatures drop into the mid-30s F (keep an eye on the weather forecast).
Here are a few good places to protect your plants from the cold:
- Garage
- An enclosed porch
- Heated room
- Heated greenhouse
2. Water Plants Deeply
Watch your local weather forecast and water your outdoor plants the morning before a freeze, focusing on the soil and not the leaves (as wet leaves can freeze). For Lauren Goldsby, Extension agent from the University of Florida in Bay County, which experienced historic winter weather in early 2025, this is where many homeowners make mistakes.
“They (homeowners) don’t water the plants well before a freeze. In areas where it is not cold enough for the ground to freeze, this helps keep the root system warm and reduces cold stress damage,” she says.
Mitchell explains that watering properly also helps your plants to stay healthy enough to endure harsh weather.
She says, “My first suggestion for gardeners is to select plants that are hardy for your growing zone so additional cold protection isn’t necessary. If you already have tender plants (plants that are sensitive to cold temperatures) in the garden, keep in mind that healthy, well-watered plants are more resilient to cold.”
Before watering, check your soil’s moisture levels to avoid overwatering. Soggy soil has less oxygen, and can end up killing the roots or making it easier for fungi to attack them.
See Related:
- How to Water Your Lawn in Fall and Winter
- The Best Time to Water Your Garden
- How to Water a Vegetable Garden From Seedling to Harvest
3. Apply Mulch Around Plant Bases
Mitchell suggests using mulch for hardy plants (plants that are adapted to local year-round temperatures): “For hardy landscape perennials, simply irrigate (if dry) and add about 2 inches of mulch. The water and mulch help to insulate the roots.”
You can use wood chips, pine straw, leaves, or other organic mulches. If the weather forecast is showing a colder night ahead, add an additional 1.5 to 2 inches of mulch that morning to trap the heat in the soil.
See Related:
4. Cover Vulnerable Plants
If you’re expecting a freeze or frost during spring, cover your tropical plants and annuals (and avoid planting warm-season vegetables early in the season). It is important to cover your plants when temperatures fall into the mid-30s F (before temperatures drop to 28 F or below). If temperatures rise again in the morning, you can remove the covers during the day.
“The most common mistake (homeowners make) is waiting until the temperatures drop before taking action,” says Mitchell. “Frost blankets work by trapping heat around the plant and need to be installed before the temperatures drop (to the mid-30s F or lower).”
Be mindful of what material you use to cover your plants. Mitchell says, “Lightweight and breathable fabrics, such as frost blankets, old sheets, or burlap, are best for providing frost protection. The goal is to trap some heat without holding excess moisture. Frost blankets designed for garden use provide the most consistent protection and can be reused for many seasons.”
When asked if there is any material they advise against, both Mitchell and Goldsby agreed that plastic is a no-go. They explain that plastic can cause overheating and heat damage on your plants, but you can use it if you make sure to remove it during daylight hours.
| Pro Tip: It is also important that the material doesn’t touch your plants directly (with shrubs and trees being an exception). Additionally, “whatever you use to cover should go all the way to the ground … to effectively trap heat,” says Goldsby. Mitchell provides a great example of how to cover woody plants correctly: “Instead of a lollipop, small trees and shrubs should be covered to look more like a ghost.” |
5. Add Lights for Heat
You may have tried covering your plants in the past, but still experienced frost damage. If so, try using Christmas lights as an additional heat source. Place them under the cover to keep heat in and prevent them from getting wet. Also, ensure the lights don’t touch your plants, as you risk burning them, and opt for incandescent (not LED) lights specifically rated for outdoor use.
Another tip is to place a milk jug filled with water near your plant roots, under the cover. The water will absorb heat during the day and slowly release it during the night. Make sure the jug doesn’t touch the plant, as this can cause the plant to freeze due to condensation.
6. Create Cold Frames
Cold frames are small greenhouses: bottomless boxes with clear covers. Think of a raised garden bed with a top on it. A cold frame protects plants from wind, rain, and frost — elements that might harm sensitive or young plants.
The structure absorbs heat during the day and releases it at night, maintaining a stable temperature for the plants inside. Cold frames are a good option to protect:
- Tender seedlings
- Recently-purchased transplants
- Warm-season vegetables
- Summer annuals
- Plants that are sensitive to frost
FAQ
A frost happens when ice forms on the plants’ surface, usually when temperatures drop to around 33 F to 36 F. Frost tends to damage sensitive species (special varieties and young plants) or plants that have broken dormancy (plants that were planted in early spring or that were fertilized late in the fall.
If temperatures drop to 32 F or below, that’s when a freeze happens. At such temperatures, the cold affects plant cells, damaging the plant tissue. Freeze damage is more extensive, and causes plants to wilt and even die.
Avoid watering immediately after a freeze, as root activity has slowed down due to cold temperatures. Wait for the temperatures to rise (with no risk of frost or freeze) and the soil to be dry before watering. Once the soil is neither frozen nor wet, you can water it lightly until you see the plants start to recover from any damage.
Avoid pruning while there is still a risk of another freeze. Goldsby explains, “If the cold damage has left soft tissue that is rotting, you can remove that. But dead or damaged leaves serve as protection for the plant throughout the rest of the winter. Pruning after cold damage can also encourage the plant to start growing before it is safe to do so.”
When to Call a Pro
Having a hard time preparing your plants for winter? Or maybe you simply don’t have the spare time. In either case, call one of LawnStarter’s landscaping pros to help protect your plants from the cold.
Sources:
- “All About Cold Frames.” By Aaron Steil, consumer horticulture Extension specialist. Iowa State University.
- “Frosts and Freezes.” Texas A&M AgriLife Extension.
- “How to Protect Plants from Frost and Freeze.” By Aaron Steil, consumer horticulture Extension specialist. Iowa State University.
- Karen Mitchell, consumer horticulture Extension specialist at Purdue University, West Lafayette, IN. Personal interview.
- Lauren Goldsby, commercial and environmental horticulture agent at the University of Florida/IFAS Extension, Panama City, FL. Personal interview.
- “Plant Protection for Freezing Temperatures.” By Randy Forst, consumer horticulture Extension educator. University of Arkansas System.
Main Image: A gardener uses a frost blanket to protect plants from freezing temperatures. Photo Credit: Olga / Adobe Stock
