Freeze warning prompts action for tender plants

Published 12:00 am Tuesday, April 15, 2014

SALISBURY — The National Weather Service has added a freeze watch to its earlier freeze warning.
The freeze warning is in effect from 11 p.m. tonight through 10 a.m. Wednesday. The freeze watch is for midnight to 9 a.m. Thursday. Temperatures will drop into the 20s by Wednesday morning and into the low 30s Thursday.
A warning means sub-freezing temperatures are highly likely. A watch means sub-freezing temperatures are possible. The Weather Service says these conditions could kill drops and other sensitive vegetation.
Darrell Blackwelder, director of the Rowan County Extension Service, offers these tips for people who may have started their gardens or put their plants outside:
Frost and cold damage depends not only on how cold it gets, but the duration of the cold temperatures. There may be little one can do in some instances; however, homeowners may reduce potential damage.
Physically protecting the plants gives some degree of protection. Burlap, sheets or blankets can be used as a protective cover. Garden centers now have spun fiber materials designed especially for frost protection. Coverings should extend to the ground in order to retain heat lost from foliage and the ground.
If you use plastic, make sure it does not touch the plant’s foliage. While plastic is ideal for trapping moisture and heat radiated from the soil, it can create additional problems unless it is removed during the day or covered to prevent temperature buildup. The extra heat, at best, will speed up growth of buds, making them more susceptible to a late frost. In some instances, tender new foliage can be cooked from the high temperatures that build up under the plastic.
Commercial nurseries, vegetable and strawberry producers irrigate to prevent frost damage. Some may also use protective row covers in addition to the overhead irrigation. Constant irrigation during freezing weather keeps plants at a constant temperature, protecting buds, flowers and fruit from serious damage. Commercial growers have special frost-proof nozzles and the ability to pump water for many nights if necessary. This is a complex and costly method of frost protection and is not recommended for homeowners.
Darrell Blackwelder is county Extension director, Rowan County Center, North Carolina Cooperative Extension; 704-216-8970;,,