Freezing temps expected this week

Protect those plants, pets and pipes. Low temperatures could dip below 32 degrees for at least four days.


Published: Friday, January 1, 2010 at 6:01 a.m.
Last Modified: Thursday, December 31, 2009 at 10:45 p.m.

If residents didn't take precautions to protect plants and pipes during the area's first freeze, it's time to rethink that strategy.

Forecasters warn of hard freeze conditions predicted to start this weekend.

Weather predictions from the National Weather Service in Jacksonville put area lows below freezing starting tonight.

Low temperatures could dip below 32 degrees for at least four days, with highs reaching only the 50s.

The low temperature predicted in the Gainesville area Saturday night is 26 degrees, 24 degrees Sunday and Monday nights and 23 degrees Tuesday night. Lows the same nights in Ocala are expected to be only one or two degrees higher than those in the Gainesville area.

A hard freeze is when the temperature is 27 degrees or lower for several hours.

The state's Florida Division of Emergency Management warned this week that residents and visitors should prepare for an anticipated long stretch of cold winter temperatures with even colder nighttime temperatures. Freezing temperatures are expected for five to seven hours inland and two to four hours near the coast with freeze warnings for a large portion of North Florida. Central and South Florida shouldn't see freezing temperatures but will experience lows in the 30s. Wind-chill values could dip as low as the low to mid-30s as far south as Lake Okeechobee.

That, commercial horticulture extension agent Aparna Gazula said, is the kind of weather forecast that should get people busy taking in or covering plants.

"When you have freeze events that last for a long time, there's tremendous potential for damage to plants," said Gazula, who is with the Alachua County Cooperative Extension Office.

The temperature during a freeze, when it occurs and for how long are all factors that gauge how damaging a freeze will be.

"If you are going to have a really long duration of frost conditions, that's when the most damage will be done," Gazula said.

The Gainesville area's first freeze Monday night and Tuesday morning lasted for only a short time and didn't get as cold as predicted.

That means it's unlikely plants in the area experienced much damage, Gazula said.

However, she said plants might have fared worse in some sections of North Florida where temperatures dropped lower than 32 degrees, the official low for Gainesville recorded by the weather service overnight Monday. The low for Ocala was 30 degrees, meteorologists said.

Signs a plant has been ravaged by the cold depend on the type of plant. Ornamentals, vegetables and plants with succulent leaves may look wilted and translucent. Other plants may appeared burned by the cold and have brown spots.

But even if a plant was damaged this week, now is not the time to be pruning it. "Hold off until spring," Gazula said. "If there is leaf or stem damage, I would just leave it like that now."

The time to take precautions to protect plants, even those that might appear to already have some damage, is ahead of the forecasted freezing conditions.

"Earlier this week, it wasn't such a big threat as it is now," Gazula said about the upcoming cold weather.

Plants in pots that can be taken indoors should be moved inside, particularly plants that are more susceptible to the cold than others. Tropical and summer annuals cannot take temperatures below freezing, and many are injured by temperatures below 50 degrees.

If plants can't be moved, they should be clustered together and covered with a freeze cloth, a sheet or plastic tarp to keep them warm.

Freeze cloth is available at horticulture stores as well as other stores that sell plants and plant supplies, Gazula said. It comes in larger sizes, making it easier for residents to drape over plants.

Remember when covering a plant that it should be done before sunset, when temperatures will drop. The cover should touch the ground and extend over the whole plant.

"The main reason why you are covering them is you want to provide insulation," Gazula said.

When the temperature falls, warm air still in the soil rises into the cocoon created by the cover. If the cover doesn't touch the ground, it's not going to create the warm bubble that will protect the plant, she said.

The cloth or plastic tarp should not touch the plant because that also can cause damage, cooling the plant wherever the two touch, according to some plant protection tips.

Plant covers can be removed during the day if the plant will get sun, if temperatures warm up to the 50s and if residents can recover the plant before nightfall when freezing temperatures will return.

Other tips to help plants include watering them 24 to 48 hours before a freeze so dry soil and wind won't increase plant damage, and moistening the soil so it will absorb daytime heat and maintain ground temperature.

"Moisture in the ground will provide heat under the plants," said Hubert Buckley with Buckley Irrigation.

Otherwise, Buckley recommended turning off sprinkling systems during a freeze. Unlike colder climates, the ground usually doesn't freeze in Florida, meaning sprinkling systems don't face the same risk as those in colder climates where it's recommended sprinklers should be "winterized" by being drained.

Turning off the sprinkler is enough, he said.

But, Buckley added, residents should take precautions with back-flow preventers, which stick up above the ground about a foot higher than the highest sprinkler in the system and are required for anything that hooks to the city's water system in Gainesville. Like pipes exposed above ground, back-flow preventers should be covered or insulated to prevent them from freezing. Otherwise, he said, the resident could be paying to replace any that are damaged by the cold.

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