Does Covering Your Plants Before A Deep Freeze Really Help?

With a layer of protection, your plants can weather frosty temperatures.  

When crisp autumn air starts rolling in, take measures to protect your garden from the inevitable cold snap. To keep all of the hard work you did in spring and summer from going to waste, start preparing your plots for Jack Frost's arrival. First, stay alert for freeze warnings in your neck of the woods. Determine frost dates in your area by consulting your local Cooperative Extension Service or consult online resources like The Old Farmer's Almanac frost calendar. They list the first day of a light frost (29 to 32 degrees) as the first frost date. As you're bundling up in your winter coat, don't forget to do the same for your plants.

Freezing temperatures are harmful to plants because when ice builds in their cells, it kills the tissue and damages them (sad, droopy brown leaves can be a warning sign). Tropical houseplants and tender summer annuals can't handle a deep freeze. If they're potted in containers, bring them indoors; otherwise, pull them up for the season. Summer-loving herbs and vegetables—like tomatoes, cucumbers, and peppers—can't withstand cold nights either, so collect your final harvest and pull them up too. Cool-weather veggies like broccoli, lettuces, collards, turnips, and Brussels sprouts can stay planted in their patch. According to The Old Farmer's Almanac, some crops like carrots, broccoli, and Brussels sprouts even taste better after going through a frost, because the plants develop more sugars.

For the best chance at success for keeping your garden alive through the winter, choose hardy native plants that are used to your area's climate. When the weather forecaster warns of an overnight freeze, cover your plants with burlap, an old sheet or blanket, or clear plastic. Use stakes or another support to keep the covering from directly touching the plants. Covering plants helps protect them from a freeze because it helps retain heat radiating from the soil and keeps them warm overnight. First thing in the morning, remove the covers to prevent condensation from developing on the leaves. Sometimes one-off frosts come early in the season, and it's worth taking the time to protect your plants because there may be a few weeks of milder weather following the cold snap.

To really ensure your plants stay toasty, cover the ground around their roots with a good layer of leaves, straw, pine needles, or mulch, which will also help lock in heat. And if you only have a few plants to protect, The Old Farmer's Almanac suggests making mini-greenhouses with recycled 2-liter soda bottles or milk jugs. Covering the plants before dusk will trap more warm air and be more protective.

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