By: Staff Reports | Gwinnett Citizen

Late season freeze can damage susceptible plants
By Tim Daly
Gwinnett County Extension Agent

In March, spring starts to make its appearance. With warmer temperatures, many flower plants begin to leaf out and bloom. The stores have warm weather plants for sale such as petunias, marigolds, tomatoes, peppers, and others.

The temptation of many gardeners is to believe that the danger of freezing temperatures has passed, and the time has come to plant these summer plants. However, below-freezing temperatures are still a possibility. The average last date of frost in our area is April 15th.  If frost tender plants are planted before this date, they are at risk for a late season freeze that can cause damage or death.

Fruit trees, saucer magnolias, dogwoods, and other spring flowering trees and shrubs set their buds in the summer and fall of the previous year. The unopened buds are more resistant to cold damage. On the other hand, flowers that have begun blooming early, along with tender vegetative growth, are more likely to suffer from below-freezing temperatures. Many fruiting trees and plants, such as apples, peaches and blueberries, along with ornamental flowering plants, once in bloom, are at risk of freeze damage. Every few years, a late season frost will hit in late March or early April and cause damage to these plants. Significant damage to fruit crops can occur because the flowers are harmed and are unable to be pollinated by insects. Most of the plants survive but produce little fruit. Commercial fruit growers can suffer major economic loss, as a result.

Tender annuals, such as vegetables and annuals, often are killed completely by the cold. The best course of action is to remove the plants and replant after the danger of frost has passed. If a late season freeze is forecasted, you can reduce the likelihood of damage by covering the tender plants with plastic or a blanket to reduce the chances of the plants suffering from the freeze. However, this will, not 100% guarantee that the plants will survive the freeze. Make sure the material is removed the following day.

Wait until after April 15th to plant cold sensitive plants. For seeds, such as cucumbers, beans, squash, and others, wait until the first or second week in May to plant. The soil temperatures will be warmer then, which will improve the germination rate of the seeds. 

Although the beauty of spring may tempt you to plant tender plants early, subfreezing temperatures pose a risk. By waiting a few weeks, you will increase the chances of your plants surviving and being productive and attractive through the growing season.

Timothy Daly, is an Agricultural and Natural Resource Extension Agent with Gwinnett County. He can be contacted at 678-377-4010 or tdaly@uga.edu