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How To Cover Plants For Frost?

Frost is a thin layer of ice, which forms when the water vapor changes from gas to solid when exposed to temperature below a freezing point.

It can damage plants when water in the plant cells form ice crystals that damage the plant tissues and interfere with fluid movement.

Frosts usually occur on calm and clear nights with little or no cloud to reflect heat to the ground and with no or little wind to diffuse warmer air in some places.

Then the cold air descends to the lowest point, with the warm air rising and moving away from the ground.

How To Cover Plants For Frost

On such nights, frost can occur even if the thermometer temperature does not exceed the freezing point. Provided the air temperature in the soil drops below 32°F, ice crystals may still form on the plants.

This can stop the fluid movement within the plants, dehydrating their tissues and drying them out. Therefore, frost damages the leaves by making them shrink and turning black or dark brown. Plants can then die if left in frost for too long without much protection.

To protect your plants, you are supposed to cover them to prevent the moisture from freezing. Since the unexpected frost can sometimes be confusing to many gardeners trying to find something to cover their plants, it’s prudent to use the right methods.

Here is how to cover plants for frost.

How To Cover Plants For Frost

1. Choose Frost-Resistant Plants

Certain flowers and vegetables are hard to thrive in the cold. However, plants of this type are hardy since they can withstand a certain amount of short-term frost. In contrast, plants that die or are seriously injured at low temperatures are susceptible.

Calendula – Frost Resistant Plants

Crocuses often cut through the snow to bloom, and spring storms rarely stop tulips, narcissus, pansies pause, or grape hyacinths.

Also, there is a wide selection of delicious frost-resistant tasty edibles, including broccoli, calendula, cabbage, carrots, lettuce, chives, leeks, radish, peas, Swiss chard, and spinach.

Local nursery experts are a good source of information on frost-resistant plants suitable for your region. Native plants, especially native perennials, are probably the best options.

2. Place the Plants in Frost-Resistant Locations

This applies to real estate in different locations. First, place the store-bought spring plants and seedlings in areas, which are not likely to be exposed to severe cold.

As the cold air penetrates deep in the soils, it passes through plants found on higher ground or slopes. Therefore, it is better to place the seedlings and other frost-prone plants in such high places.

Placing plants on the fences, walls, and benches, especially if they face west or south, can provide extra protection, particularly if structures are dark. The structures absorb heat during the day.

They diffuse this heat during the night and keep the plants warmer than usual. Neighboring shrubs also protect against light frosts.

3. Add a Thick Mulch Layer

Like wearing a sweater in cold weather, a mulch layer on the plants help to protect the soil from any sudden temperature change.

Use leaf mold, wood chips, straw, or even some leaves to offer important cover to the plants. Apply thick mulch to a depth of between 3 and 6 inches to create the best barrier.

Leave an opening of about an inch or two around the center stem to allow warmth from the soil to go through the plants. While the garden bed is the best thing you can do to keep things low, it is best to remove some of these mulch in warm weather.

4. Harden Off Seedlings

Before placing the seedlings, arrange them outdoors and gradually expose them to fresh air. This process is known as hardening off, which will help you make your plants grow stronger and better and withstand the frost.

Start a process of hardening off around 14 days before the transplant. Then, in a mild climate and above 45 °C, place the seedlings outdoors in a warm and shady area and sheltered from the wind.

You can bring them back at night. After two weeks, your seedlings may be sturdier and stronger, ready to be transplanted.

5. Cover Individual Plants with The Cloche

The cloche is the bell-shaped cover, which is made of glass or plastic that keeps the plants small and warm in cold weather. You can buy plastic garden cloches because you can reuse them during the fall or inclement spring weather.

SYITCUN Protective Garden Cloche Reusable Plastic How To Cover Plants For Frost
SYITCUN Protective Garden Cloche Reusable Plastic via

If you are in a hurry, there are plenty of things around your house that may be used, like a cloche. Turn the flower pot or bucket upside down to do this trick.

Or cut the bottoms of the plastic milk jug and place them on the soil. If you use the cloche, cover the plants just before dark and then uncover them in the morning so they can enjoy the energy and warmth of the sun.

6. Use the Blankets

To cover many plants from frost, cover them with blankets. Place some sticks around the plants so that when you cover them, they create a tent-like texture.

Let the material cover the plants on the surface of the soil lines. Please do not hold it around the stem or trunk of the plant because tying it will prevent soil warmth from passing through the plant.

Valibe Plant Covers Freeze Protection
Valibe Plant Covers Freeze Protection via

Increase frost resistance by adding a final plastic layer; for example, an old shower curtain or tarp would suffice. Just make sure no plastic cover comes in contact with the foliage plant, as plastic may damage the plant.

Weigh down the edges and corners with heavy bricks or stones to prevent the cover from being blown away overnight. Just before nightfall, these blankets must be removed the next morning.

If dealing with a frost threat is a repetitive theme in the garden, you can invest in specifically designed, breathable, and reusable frost blankets, which may be cut into different sizes.

On very cold nights, thermal mylar blankets with aluminized sides facing the plants can help you reflect 99 percent of heat to the ground.

7. Warm the Plants with The Water Jugs

Fill the plastic jugs with water and then place them in sunlight to allow them to soak up the heat throughout the day. Before dark, place the jugs around and cover your plants. The water inside loses heat very slowly than air and soil, and warmth provide cover to the plants during frost.

8. Bring the Potted Plants Indoor

When the frost is expected, bring hanging baskets and flower pots inside. The potted plant roots undergo greater change temperature than those being planted in the soil.

Therefore, they will reach lower temperatures, and for this reason, the potted plants are particularly susceptible to root damage because of frost.

This can cause the roots, especially those near the pot edge, to turn black and spongy. Even though root damage cannot kill a plant, it slows its growth.

When you bring the potted plants inside, make sure they are free of insects or pests and not suffering from the diseases. Not only can this exacerbate the problem, but it can also infect other plants.

If you decide to cover the hanging basket instead of bringing it inside, you can put it down first and place a cover on the basket to benefit from the relative warmth from the ground.

9. Wrap the Fruit Trees

The young trees, which are between 1 and 4 years old, can be prone to frost injuries that can kill them immediately. Also, blossoms and buds of the fruit trees exposed to frost during the spring can slow down their growth and lead to lower yields during the growing season in other years.

Citrus fruits are especially sensitive to frost and must be protected if the temperature goes to 29 °C.

To cover these trees from frost, wrap the trunks using towels, cardboard, pipe insulation, or rags. Also, you can use felt or burlap tree protector wraps.

Please start at the bottom of the trunk and wrap it around, making sure the layers overlap a few inches. Next, wrap it up to the bottom of the tree.

Finally, tie the wrap with some waterproof or twine tape. If the temperature rises to 26 °C for a long period, add the plastic sheeting to the wrap to cover plants from frost.

10. Make the Air Moving

If frost threatens large areas of commercial agriculture, many farmers use a variety of tactics to create the wind. One such tool is the selective inverted sink, a large chimney fan that draws cold air away and up, pulling warmer air toward the ground.

Another way is to order multiple low-flying airplanes to fly over the crops to maintain airflow. However, since neither of these solutions is practical for home gardeners, this air movement concept to cover frost can be used on a smaller scale.


Of course, different plant covers can be bought specifically to protect plants from frost. They can be more attractive and can work well for many plants to keep the flowers in your garden frost-free. However, when you try to protect your plants from frost fails, you must let nature takes its course.