Winter in central Florida is subtle but very real, with furnaces and sweaters needed rituals some of us look forward to after another sweltering summer. Sure, the last times it snowed here were 1977 and 1989, but every winter brings us a few frosts or even freezes. And as the chill brings a sweetness to ripening citrus, our northern friends and relatives shovel mountains of snow and scrape ice off windshields, their entire yards dead for months on end. For Florida gardeners, winter is a trusted friend and occasional foe.
We all love it when that first good chill zaps mosquitos and fleas and summer garden pests like stinkbugs. A long hard cold spell gives our borderline nectarine and apples a better chance of blooming and fruiting. Roses also appreciate a bit of winter rest, and all our cool weather veggies and annuals glory in those nippy nights we curl up in flannel jammies. And the goldfish and koi in our ponds love the cold water as they only tolerate summer’s heat.
But a hard frost or outright freeze with temps in the 20's is common enough for us to have ready several easy cheap strategies to protect our tropicals that may be frozen down to the soil line if unprotected.(But even that can be a blessing in disguise, forcing a long overdue pruning!).
My first choice is to give my entire yard a deep soaking in the daytime before the freeze arrives that night. Well watered plants resist freeze damage better and thoroughly dampened soil holds more latent heat. Citrus and strawberry growers take this one step further and run sprinklers at night to coat their crops with ice as an insulation against temps lower than 32 degrees.
A second easy measure is to cover just before sundown all your tropicals with bed sheets and blankets (not plastic as it conducts cold into the plants) to trap the day’s warmth. Use bricks and stone to hold the edges down onto the soil to keep cold air from oozing in. After the freeze passes, just launder all your "plant savers".
Another variation on this theme is to invert plastic garbage cans, 5 gallon plastic buckets and cardboard boxes over plants before sundown to trap the heat released from the soil at night....a brick on top on a windy night will hold them in place.
Putting a heat source beneath these covers will do wonders to get tropicals through even a hard freeze like the doozies of 1977, 83 and 89....a gallon milk jug filled with HOT tap water and tucked beneath a cover just before you hit the sack can make all the difference between that begonia making it and not! Some folks use strands of big old fashioned Christmas lights (not the little twinklers) or a simple table lamp with a 100 watt bulb on an extension cord as well as water bed heating pads. I have used votive candles to heat the air inside an inverted garbage can protecting a treasured plant but this would be a fire hazard beneath sheets and blankets. A combination of a blanket and Christmas lights can save that huge staghorn fern you’ve nurtured for years. Think "heat" and how to trap it.
But how to protect trees and other plants too big to cover? Again, copy the wise citrus farmer.....a box fan on an extension cord aimed up into a citrus or papaya or banana on one of those perfectly still COLD nights will keep the air moving, plus the electric motor releases some waste heat. A simple barbecue grille loaded up with charcoal and lit before you sleep can send a precious column of heated air up into a treasured palm or citrus for a few crucial hours. Or aim an infrared spot lamp up into the plant as that will warm the stems and leaves directly while the bulb heats the air rising past it. Cranking up to "full blast" a heated swimming pool or jacuzzi the day before the freeze arrives can also be a key source of heat that night.
Got a small unheated greenhouse? Set a small electric heater with a built- n fan on an extension cord inside the greenhouse after you’ve packed it with all your potted plants and treasured orchids and leave it on "high". Be sure that windows and vents and doors are tightly sealed with masking or duct tape to keep out the cold and keep IN the heat.
With safety in mind, use your imagination to generate and trap heat and ward off cold, knowing that as you savor citrus sweetened by the chill our northern friends have months more of snow and ice ahead of them! Ah, isn’t Florida grand?