How to Protect Outdoor Plants From an Overnight Freeze
- Frost damages tender garden plants.first frost image by Deborah Durbin from Fotolia.com
Frost may not be a four-letter word, but it certainly can seem like it to gardeners. For tender garden plants, the fall frost often signals the end of the growing season. Taking quick measures to prevent damage may extend the growing season until the next frost threatens. - Home gardeners are no strangers to covering plants when frost threatens. Sheets, tarps and other physical barriers over the tops of plants keeps them safe from the damage of frost. According to Cornell University, covering plants keeps them 3 to 5 degrees Fahrenheit warmer than the surrounding air. For best results, drape fabric over cages or stakes to create a tent over the plants. A cardboard box over plants is also effective. If covered in late afternoon, this provides the added benefit of trapping heat as it radiates from the soil at night.
- Water plants thoroughly in late afternoon before an expected frost. According to Cornell University Extension, wet soil holds more heat than dry soil. Air above wet soil is up to 5 degrees warmer than air above dry soil. The University of Georgia extension explains that well-hydrated plants are better able to withstand damage from cold winds. When light frosts threaten, wet soil may be enough to prevent frost damage.
- Providing a steady supply of water throughout the night keeps the surface of foliage and fruit wet. Cornell's extension office explains that water releases heat as it freezes. Keeping plants wet, even if it freezes and forms a thin coat of ice on the plant, may protect the interior of the plant from damage. Water must be provided until temperatures rise above freezing and the ice melts.
