WINTER PROTECTION FOR FLORIDA PLANTS
Recorded at a talk presented to the RFCI Tampa Bay Chapter by Stan DeFreitas
Stan reminded us that, despite the warm weather we've been having, the cold weather is coming. Most of us wait until the last minute, the 11th hour, to do anything about it. He says he's the same way, though he's lived all his life in Florida. Yet, he waits until Roy Leep says, "Well, it's going down below freezing."
"What am I going to do? Start covering things up, bringing things in." My wife says, "Every year you wait until the last minute."
One thing Stan recommends is something that he has done; build a structure in the back yard. His is a geodesic dome-type structure which he covers with plastic and in which he crams all the plants he can possibly get in there. He has pineapples, bananas and other tender plants. This is one of the best ways to protect tropical plants in the winter in this subtropical area where temperatures go down into the 20s or even the teens (Fahrenheit). Many plants can be grown in containers, small plants during the winter may be dug up and carried over in a holding area. A small electric heater keeps his geodesic dome warm enough to prevent freezing of the plants.
Another approach to winter conditions is to go to more cold-hardy trees, such as peaches, plums, apples, persimmons, etc. Stan has two peach trees in his back yard that are approximately 15 feet tall and produce large juicy peaches. He suggested in the selection of citrus fruit to avoid the tender fruit such as lemons and limes and go to the more hardy citrus such as grapefruit and some of the oranges. It is also wise to select cold-hardy varieties among other fruits. Avocados, for instance, come in a small cold-hardy variety that will take the cold of central Florida.
Stan next mentioned the watering approach for protection of plants during a freeze. It is the process in which sprinklers are run through the cold period to provide protection with the relatively warm water from the sprinklers. He doesn't recommend this method for the general public because it requires at least a third of an inch of water per hour to provide the protection needed, and this would result in two inches of water in a six-hour night. Sprinkling must begin before the freezing temperature is reached and continue until after the temperature rises above 32°F. If you are going to use this method, you would be advised to buy some rubber boots because your yard will probably end up a lake, and be aware that the ice which forms on the branches can also cause considerable damage. But if you want to use this method of cold protection, you should check your sprinkler system now to make sure it will produce sufficient water to protect the plants, because with insufficient water, you may cause more harm than good. However, watering plants before a freeze is good policy. The plants should not be too dry when the freeze comes and it is wise to water well after the freeze.
And we should remember that damage is not only caused by the low temperature but also by the wind, which tends to desiccate the leaves and lower the chill factor, which contributes to the damage. Another thing which contributes to the damage is a sudden change. Cooler weather tends to harden the plants if it's not below freezing. Warm weather tends to keep the plants in a state of active growth. A drop of 25 to 30°F in two or three hours is not unusual in this area and this contributes very definitely to the extent of damage.
Mulch is a good insulator. Just as Plant City farmers cover strawberries with straw during freezes, you can mulch over your plants when a freeze is expected. Also, if you have the time and if the sun is shining during the day, you can rake the mulch away from the base of larger plants to allow the sun to heat the soil and then in the evening. after the sun goes down, rake the mulch back up around the base of the plant to retain the heat. A mistake frequently made in covering plants is to place the cover over the top of the plant and not bring it all the way to the ground. If you don't cover all the way to the ground, you are not conserving the heat of the ground. Of course the cover will keep the frost off the plants if it doesn't freeze. In the use of a plastic cover, one of the don'ts is to allow the plastic to touch the plant, because the plant in contact with the plastic will be frozen just as though the plastic wasn't there. So don't drape the plastic right over the plant. Use some kind of support to hold it up and away from the foliage.
If you intend to use a heat source under the cover, be safety minded. Don't let the heat source touch the plastic or cover and don't get it too close to the plant. A light bulb under the cover may make the difference between life and death of some of your plants. Of course the light bulb must be plugged in and turned on. The environmental heater, the new name for the old smudge pot, is a helpful item in your garden.
Another thing to consider is fertilizing. Lots of people say, "Don't fertilize in the fall", and the rule many years ago used to be "Put your plants to bed hungry". That's not the rule anymore. It has been proven that a plant that has been well fertilized late in the fall will go through the winter better than a plant that has been starved, or that has been injured by insects or disease. Also, Stan recommends fertilizing lightly through the winter, which normally keeps the plants strong and growing vigorously and more likely to bounce back if they do get damaged. Another rule is not to go out and trim your plants back immediately after they are damaged. Damaged foliage gives some insulation or coverage from frost for the undamaged parts of the plant.
Trimming the plant tends to activate the lower buds and cause the plant to blossom out sooner than it should. The proper approach is to wait until spring, at which time it is more easy to discern the extent of damage.
The next thing we looked at was insulation. Often, you can wrap smaller plants and trunks of larger plants with insulation. If you can protect the trunk, even though the branches are damaged, the tree will come back. Insulation may be fiberglass, newspaper, blankets or whatever insulation material is available.
DATE: March 1986
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