How to protect your plants during the last frost or freeze

COLUMBIA, S.C. — The first day of Spring is quickly approaching and warmer temperatures and high pollen levels have already returned to start the new season. Spring will begin on Thursday, March 20. Many are eager to get outside and plant their spring gardens, but it is important to be cautious early in the planting season to protect your plants from the last bit of the winter cold. 

As the winter season draws to a close, the last freeze and frost of the season are important milestones, especially for those involved in agriculture and gardening. The timing and intensity of late-season cold events can have significant effects on plants and wildlife.

Frost occurs when the temperature of the air near the ground drops below freezing, causing water vapor in the air to form ice crystals on surfaces like grass, leaves, and vehicles. Frost forms through the night when cooling from the daytime happens. Conditions that can lead to frost are clear skies, calm to light winds, and cool temperatures. The cooler the temperature is, the more likely frost is to form and the more widespread it will be. Frost can still form, even when temperatures are slightly above 32 degrees.

A freeze refers to temperatures reaching or falling below 32 degrees for a longer period of time. A freeze typically lasts longer and has more severe effects on plants and agriculture. A “hard freeze” is a common phrase used when temperatures fall well below freezing for an extended period of time. 

Here in the Midlands, the average time for the last frost/freeze is from the last week of March through the first week of April.

It is important to monitor weather conditions and overnight temperatures during this time to know when you may need to protect plants that may already be outside.

To protect plants from frost use blankets, sheets, towels, or even cardboard to cover plants. It helps to cover plants before it gets dark to trap the warmth they’ve absorbed during the day.