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DALY: Even with warmer weather, a late season freeze still possible

Timothy Daly

Timothy Daly

This winter has been one of the worst in recent memory. With the single digit temperatures combined with the winter precipitation, everyone is anxious for the arrival of warmer temperatures. However, even with the recent mild weather, the risk of a late season frost has not passed. The average last date of freezing temperatures in our area is April 15. Planting anything that is not cold hardy prior to that date is at risk of suffering freeze damage.

Most spring flowering shrubs and trees, such as fruit trees, set their buds in the late summer and fall of the previous year. These unopened buds have a greater resistance to the cold temperatures. However, newly opened flowers and young tender vegetative growth is susceptible to freezing temperatures. Peaches, apples and blueberries, major commercial fruit crops in Georgia, are among the earlier flowering plants and can be damaged by freezing temperatures. Saucer magnolias, Bradford pears, and cherry trees can also suffer the same fate.

On Easter Sunday in early April 2007, a late season frost occurred with temperatures falling into the twenties. The frost extended well into the southern part of the state. The majority of the fruit crops were lost. Most of these trees did not bear fruit since their flowers were damaged. This damage prevented the pollination process that leads to setting of the fruit. The freeze also caused harm to plants in the home landscape. Although the new growth on established landscape plants suffered cold damage, most of these plants survived.

After the 2007 freeze, the Gwinnett Extension office received numerous calls from people who had planted tender vegetable plants, like tomatoes and peppers, as well as herbaceous flowering plants, that suffered freeze damage. They wanted to know what could be done to save their plants. The homeowners were advised to remove and dispose of those plants. They were most likely dead and should be replaced after all danger of frost has passed.

If a late season freeze is forecasted, cover young tender plants with new growth and open flowers with a sheet or plastic cover to give some protection. However, this action does not guarantee the plants will survive freezing temperatures. Do not forget to remove the covering the following day.

Although they may be for sale at local garden centers, avoid planting cold sensitive plants until after the danger of frost has passed in the middle of April. Plant seeds, such as squash, cucumbers, and beans, after May 1 when the soil temperatures are warmer. Before then, the colder soil temperatures may delay germination of these seeds. You can start the seeds indoors in small containers, such as peat pots, and then plant them outdoors. Transplant seedlings can also be purchased at local garden centers.

Resist the temptation to put out plants that are not tolerant to below freezing temperatures now. In a few weeks, the risk of a freeze will be gone, and the planting can begin.

Timothy Daly, MS, is an Agricultural and Natural Resource Extension Agent with the Gwinnett County Extension. He can be contacted by phone at 678-377-4010 or by email at timothy.daly@gwinnettcounty.com.