All Weather News

Coping with Frost

23 Sep 2012, 12:13 pm

Coping with Frost

On this first full day of fall, temperatures dipped down into the 20s and 30s across the Midwest.  A few records were broken and there were even a few areas in the teens – check out Langdon, ND and Fosston, MN.  But this is still September and typically we can expect the growing season to last at least a few more weeks in most of these areas.  My mums are still in full bloom and I’d hate to see them die off so early!  I dug up a few tidbits on the do’s and don’ts of protecting the plants in these types of situations.

First of all, before you waste any time, determine if the situation is one in which your efforts will even be beneficial.  That depends on what weather pattern led to the dropping temperatures.

From Colorado State University:

“Advective frosts occur when a cold front moves into the area. Temperatures may drop significantly below critical levels, thereby making crop protection questionable.

Radiation frosts occur on calm clear nights that lack cloud cover to hold in heat. Radiation frosts at the beginning and end of the growing season are typically only a few degrees below critical levels making crop protection worthwhile.”

The circumstances that led to this morning cold temperatures would best be described as the Radiation frost so its worth the time to protect the plants.


How it Works

From Colorado State University:

“The sun warms the soil in the daytime.  Heat from the soil keeps crops warm at night.  A covering traps heat from the soil around the crops. “

Similarly, cloud cover often prevents temperatures from dropping throughout the overnight hours as it provides a layer of insulation.

Covering Up


“A fabric covering will allow moisture to escape but will still protect plants from frost by preventing the freezing air from coming into direct contact with the moisture. Bed sheets work well for covering large plants and shrubs, as well as young sprouts. Newspaper can be used on low-growing foliage, but won’t stay on top of larger plants well. In a pinch, you can use plastic sheets, but be sure to remove the plastic covers early in the morning to let the increasingly warmer daytime air reach the plants. If the threat of frost is prolonged and temperatures remain low during the day, be sure to use a fabric covering. When there is a threat of frost, cover your plants before sunset.”

Some Can Handle It

From The Green Bay Gazette:

» Likely damaged by light frost:beans, cucumbers, eggplant, muskmelon, peppers, pumpkins, squash, sweet corn, tomatoes, New Zealand spinach, watermelon

» Can withstand light frost: artichokes, arugula, beets, carrots, cauliflower, celery, Chinese cabbage, lettuce, endive, parsnips, peas, Swiss chard

» Can withstand hard frost: Brussels sprouts, broccoli, cabbage, kale, kohlrabi, leeks, mustard greens, onions, parsley, peas, radish, spinach, turnips

As a general rule, plants that are farther from the ground are more likely to be damaged by frost, as the ground still radiates warmth in the fall. Light frost makes some leafy greens and roots vegetables sweeter, so consider keeping kale and carrots in the ground until you’re ready to eat them.

From Organic Gardening:

“The good news is that flowering bulbs are remarkably resilient. Most will not be fazed by limited periods of cold weather, says Steve Zwiep, Parks Department supervisor for the city of Holland, Michigan, home of the annual Tulip Time Festival. “We’ve had snow a foot deep and packed around the tulips. When the snow melted, the tulip buds were fine and ready to go,” Zwiep says. The risk of damage is greatest, he explains, when the plants are blooming.”

Don’t Prune

From Dave Cald:

“Don’t prune your plants and flowers. If after all of your effort, the frost still managed to cause some damage, don’t cut off the damaged parts. These dead leaves and stems will provide a little insulation, helping protect your plants and flowers from further frost damage. It is very important to protect your plants and flowers from frost. You’ve worked hard all spring and summer raising these plants and flowers. Just a bit more effort can extend the lives of your plants and flowers by several weeks, and with a little help from Mother Nature, possibly months.”

Here’s an idea for the spring frosts:


Yes, those are plastic soda bottles.

“Plastic bottles with the bottoms cut are placed over flower bulbs to protect them from the frost near the sea shore in the Black Sea harbour of Constanta, 250 km (155 miles) east of Bucharest.” Picture taken on February 4, 2012. Reuters/Radu Sigheti

Frosty conditions will be spreading into the Ohio Valley for tomorrow morning.

Have a great weekend!

Gretchen Mishek

Leave a comment

Your email address will not be published.