Cold Protection – Frequently Asked Questions

Common misconceptions about weather in central Florida

Many residents new to central Florida think they live in the tropics.  This is not always the case, as most of central Florida, including Lake County, is in a subtropical environment.  Each year occasional freezing weather is likely to occur.

Susceptible plants to freezing temperatures

Tropical plants, warm season annuals, and warm season vegetables are most susceptible to freezing temperatures.  Ornamental tropical plants typically display brightly colored foliage and large leaves which make them appealing to the central Florida gardener.  In many cases, tropical plants will not survive our subtropical weather.  Grow tropical and tender plants in containers or as annuals.  You can incorporate them into a landscape but use a mixture of hardy and temperate plants so your entire landscape does not suffer from freezing temperatures.

Select plants to avoid damage by freezing weather 

First, look for plants recommended for your USDA hardiness zone, for example, much of Lake County is in hardiness zones 9A and 9B.  Once you know your hardiness zone, do a little research while you are plant shopping.  Next time you visit the garden center look up the names of the plants and their hardiness zone on your smartphone before purchasing.  Useful sites include https://gardeningsolutions.ifas.ufl.edu/ and https://edis.ifas.ufl.edu/entity/topic/plants.  Contact your local county extension office to provide suggestions for plant materials.

If a plant is recommended for my hardiness zone, does that mean the plant will not be damaged by a freeze? 

Not necessarily, it means that the plant will survive the conditions in this hardiness zone.  A plant may be listed for zone 9A and the foliage may still be damaged, but it will typically come back from the crown.

Helping plants survive freezing temperatures

Place tender plants near structures to block cold winds or plant them underneath tree canopies.  Try to keep plants as healthy as possible by fertilizing and watering appropriately.  Avoid late fall fertilization or pruning.  Use natural tree/wood mulches to insulate plant roots.

Steps to take when freezing weather is predicted 

First, check the soil moisture around your plants and water if appropriate.  The soil should be moist, but not saturated.  Soil moisture helps radiate heat from the ground on cold nights.  Group containers together or move them indoors.  Finally, cover plants to offer protection.

Best materials to cover tender plants 

Use fabric blankets and sheets to trap heat around plants.  Old velour blankets work well.  Avoided using plastics.

How to secure coverings 

Secure coverings all the way to the ground with landscape stakes, bricks, or blocks.  Covering plants captures and reduces heat loss from the soil and the plant.  If possible, create a structure around the plant(s) to be protected.  Drape fabric over the structure.  Where the fabric touches the plant heat loss can occur, causing foliage damage.  Uncover plants when temperatures reach above freezing.

Should water be sprinkled/irrigated on tender plants during a freeze? 

Not for the homeowner.  Citrus growers and nursery growers will do this, but they have this practice down to a science.  Growers know exactly when to start and stop watering.  A constant film of water needs to be applied to the plants during a freeze and most homeowner irrigation systems cannot provide consistent and constant application.

Steps to take after a freeze to help plants recover 

Plants are prone to desiccation during windy, freezing events.  A thorough watering after a freeze helps plants recover.

Time pruning to reduce cold damage

Wait until the danger of freezing temperatures/frost is over.  This is around mid-March for most of central Florida.  If you prune now, additional cold temperatures may cause damage further into the plant.  By leaving the frost damaged leaves and stems in place, further protection will be provided as more heat will be intercepted by the plant on cold nights.

Sources:

Ingram, D.L. and Yeager, T.H.  2003. “Cold Protection of Ornamental Plants.”  University of Florida/Institute of Food and Agricultural Sciences.  EDIS ENH1.   http://edis.ifas.ufl.edu/mg025