How to Protect Plants from Frost: A Gardener's Guide

Frost can be a serious threat to many plants, especially those that are tender, tropical, or young. Frost occurs when the temperature drops below freezing and water vapor in the air forms ice crystals on the surface of plants. This can damage the plant cells and cause wilting, browning, or death.

Fortunately, there are many ways to protect your plants from frost and extend your gardening season. In this blog, I will share some of the best methods to keep your plants safe and healthy in cold weather.

Know Your Plants and Your Climate

The first step to protect your plants from frost is to know which plants are vulnerable and which are hardy. Some plants, such as kale, carrots, and pansies, can tolerate some frost and even taste better after a cold snap. Other plants, such as tomatoes, basil, and begonias, are very sensitive and need to be sheltered or brought indoors.

You also need to know your climate and the average dates of the first and last frost in your area. You can use online tools such as The Old Farmer's Almanac or The National Gardening Association to find out this information. This will help you plan when to plant, when to harvest, and when to protect your plants.

Cover Your Plants with Cloths, Covers, or Containers

One of the simplest and most effective ways to protect your plants from frost is to cover them with a cloth, a cover, or a container. This creates a barrier between the plant and the cold air, trapping some heat and preventing ice formation. You can use materials such as:

• Fabric: You can use old sheets, blankets, towels, curtains, or any other fabric that is large enough to cover your plants. Make sure the fabric is breathable and not too heavy to avoid crushing the plants. You can also use specially designed frost cloths or row covers that are lightweight and insulating. You can buy these from or Gardener's Supply Company.
• Plastic: You can use plastic bags, tarps, or sheets to cover your plants, but make sure they do not touch the foliage, as this can cause freezing or burning. Plastic is not breathable, so you need to remove it as soon as the temperature rises above freezing. You can also use clear plastic containers, such as milk jugs, soda bottles, or buckets, to create mini greenhouses over your plants. Cut off the bottom and place them over the plants, leaving the cap off for ventilation.
• Paper: You can use newspaper, cardboard, or paper bags to cover your plants, but make sure they are dry and secure. Paper can provide some insulation, but it can also get wet and soggy, which can harm the plants. You can also use paper cones, such as those used for rose bushes, to protect your plants. You can buy these from Home Depot.

When covering your plants, make sure to cover them completely, from the top to the ground, and secure the edges with rocks, bricks, or stakes. This will prevent the cold air from getting under the cover and reaching the plants. You should also cover your plants before sunset, when the temperature starts to drop, and remove the cover after sunrise, when the temperature starts to rise. This will prevent overheating and allow the plants to get some light and air.

Move Your Potted Plants Indoors or Under Shelter

Another way to protect your plants from frost is to move your potted plants indoors or under shelter. Potted plants are more exposed to the cold than plants in the ground, as their roots are not insulated by the soil. You can move your potted plants to a warmer location, such as:

• Indoors: You can bring your potted plants inside your house, garage, shed, or basement, as long as they have enough light, ventilation, and humidity. You can also use a greenhouse, a cold frame, or a hoop house to create a warmer and protected environment for your plants. You can buy these from Amazon or Gardener's Supply Company.
• Under shelter: You can move your potted plants under a shelter, such as a porch, a patio, a carport, or a pergola, as long as they are not exposed to the wind or the rain. You can also use a wall, a fence, or a hedge to create a windbreak and a heat trap for your plants.

When moving your potted plants, make sure to do it gradually, as sudden changes in temperature and light can shock the plants. You should also water your plants well before moving them, as moist soil can retain more heat than dry soil. You should also avoid fertilizing your plants in the fall and winter, as this can stimulate new growth that is more susceptible to frost.

Mulch Your Plants with Organic Materials

Another way to protect your plants from frost is to mulch your plants with organic materials. Mulch is a layer of material that covers the soil around your plants, providing insulation, moisture retention, weed suppression, and nutrient addition. You can use organic materials such as:

• Leaves: You can use fallen leaves from your yard or your neighborhood to mulch your plants. Leaves are abundant, free, and biodegradable, and they can provide a thick and fluffy layer of insulation for your plants. You can also shred or chop the leaves to make them more compact and prevent them from blowing away. You can use a leaf shredder or a lawn mower to do this. You can buy these from Amazon or Home Depot.
• Straw: You can use straw to mulch your plants, as it is cheap, lightweight, and easy to spread. Straw can provide a good layer of insulation for your plants, but it can also harbor pests and diseases, so make sure to use clean and dry straw. You can also use hay, but it may contain weed seeds that can sprout in your garden. You can buy straw from Amazon or Tractor Supply Co..
• Pine needles: You can use pine needles to mulch your plants, as they are acidic, aromatic, and long-lasting. Pine needles can provide a good layer of insulation for your plants, but they can also lower the pH of the soil, so make sure to use them for acid-loving plants, such as blueberries, azaleas, and rhododendrons. You can also use other evergreen needles, such as spruce, fir, or cedar. You can buy pine needles from Amazon or Home Depot.

When mulching your plants, make sure to apply a thick layer of mulch, at least 3 to 4 inches deep, around the base of your plants, covering the roots and the crowns. You should also leave some space between the mulch and the stems or trunks of your plants, to prevent rotting or suffocation. You should also apply the mulch after the first frost, when the soil is cold, and remove it in the spring, when the soil is warm.

Water Your Plants Well Before a Frost

Another way to protect your plants from frost is to water your plants well before a frost. Watering your plants can help them survive a frost, as water can release heat as it freezes, keeping the plant cells from freezing. Water can also prevent dehydration, which can make the plants more vulnerable to frost damage. You can water your plants in the following ways:

• Water the soil: You can water the soil around your plants, making sure it is moist but not soggy. You should water the soil in the morning or early afternoon, giving it enough time to absorb the water and release the heat. You should avoid watering the soil in the evening or at night, as this can lower the temperature and increase the risk of frost.
• Water the foliage: You can water the foliage of your plants, spraying them with a fine mist of water. You should do this in the early morning, before the sun rises, as this can create a thin layer of ice on the leaves that can protect them from frost. You should avoid watering the foliage in the evening or at night, as this can cause freezing or burning.
• Water the air: You can water the air around your plants, using a sprinkler, a hose, or a mister. You should do this continuously throughout the night, as this can create a humid and warm microclimate for your plants. You should stop watering the air when the temperature rises above freezing, as this can cause melting or dripping.

When watering your plants, make sure to use clean and fresh water, as salt or chemicals can harm the plants. You should also use a gentle and even pressure, as too much or too little water can damage the plants. You should also monitor the weather forecast and the temperature, as watering your plants can be ineffective or harmful in extreme conditions.

Choose Cold-Hardy Plants for Your Garden

Another way to protect your plants from frost is to choose cold-hardy plants for your garden. Cold-hardy plants are plants that can survive low temperatures and frost without needing much protection. You can choose cold-hardy plants based on your hardiness zone, which is a geographic area defined by the average annual minimum temperature.