The new year is rolling in on the wings of bitterly cold winter weather that is atypical for Alabama. Temperatures in most parts of the state will remain at freezing levels this week, raising concerns for outdoor plants and infrastructure. As another cold spell hits the state, Alabama Cooperative Extension System Home Horticulture regional agents encourage residents to take the proper precautions.

Long-term, below-freezing temperatures can be severely stressful for outdoor plants. Gardening and horticulture enthusiasts should prepare for prolonged freezes to mitigate plant damage or loss of plants.

“During the winter, we will inevitably have frosts and freezes coming our way,” said Brian Brown, an Alabama Extension regional agent. “Unlike the early, hard freeze we had a couple of years ago, this year, plants should have had enough time to acclimate to the cold weather.”

Preparation
When a cold front creeps across the state, not every plant will incur damage. However, there are preventative measures to help protect the plants that may see damage. Brown said ensuring proper soil moisture is the first step.

“Be sure to water your plants as needed because soil moisture will help absorb heat,” Brown said. “A drought-affected plant will be impacted more than a well-watered one will. Mulching will also help retain soil moisture and prevent heat loss.”

Covering plants will also provide insulation for heat emitted from the ground. Lightweight cloth material — such as a bed sheet or floating row covers found at most farm supply or garden centers — will do the trick. This method traps warm air to mitigate freezing. Use sticks or posts to keep the cover off the plants. It is also important to weigh down the  material edges to keep the wind from blowing it away. Plastic is not recommended because it can damage the plant. Be sure to remove all covers when temperatures reach above freezing.

If you have plants in containers, be sure to either move them inside a garage or next to a structure to keep cold, harsh winds from damaging the roots. You can also place burlap or sheets around the containers to help reduce heat loss.

Species to Watch
Cool-season crops are hardy vegetables and can survive temperatures below freezing for short periods of time. Cool-season crops include collard greens, cabbages, onions and broccoli. Evidence of lightly burned foliage is completely normal for these crops after enduring a hard frost. However, Dani Carroll, an Alabama Extension regional agent, said certain crops may require some extra frost care. Harvest semihardy vegetables like lettuce before the freeze.

“Root crops, such as carrots, radishes and turnips, will need to be heavily mulched to prevent damage,” Carroll said. “Gardeners can use something like an empty milk jug with the top cut out to cover their vegetables.”

Carroll said plants that were recently placed in the ground may not be hardy enough to withstand long periods of freezing temperatures.

Ornamental shrubs and small trees may not immediately exhibit damage from the freezing weather. These plants should be left alone until spring when new growth emerges. The scope of damage will be much easier to determine several weeks after prolonged freeze events.

“Typically pruning dead and diseased wood can be performed anytime, but this is one time that pruning dead or damaged wood is not recommended,” Carroll said. “Be patient and wait until spring growth begins to determine the extent of freeze damage and prune accordingly.”

More Information
For more information about gardening throughout the year, listen to Alabama Extension’s From the Ground Up! Podcast or search “gardening” in the search bar of www.aces.edu.