Cold hardy citrus are a treat for north Florida gardeners. Credit: Tyler Jones, UF/IFAS
Growing citrus in the backyard is definitely a gardening perk for those living in north Florida. However, our frequent cold snaps are also a source of anxiety for many backyard citrus growers. With weather forecasters excited to highlight dips in temperature, many folks call their local extension office, or head to social media, fretting over what they should do with their citrus. This article is intended to walk you through what to consider when deciding how cold it needs to get before worrying.
First of all, you can really help yourself out by selecting and planting varieties that are known to be cold hardy. In addition to Myer lemon, calamondins, kumquats, grapefruit, and pummelo, other cold hardy citrus varieties include:
mandarins – satsuma, shiranui, Sugar Belle, Tango and Bingo
oranges – navel, Hamlin, Minneola Honeybell, and Valencia
Again, the above varieties are known to be hardy, as trees, down to at least temperatures in the mid-20s. Young trees are more susceptible to these temperatures, but once mature, you shouldn’t worry about having to cover them down to the mid-20s. Remember, when covering plants for cold protection, you want the material – whether it be fancy frost cloth or just a simple blanket – to completely cover the tree and drape on the ground. It is the heat leaving the soil that you are trying to capture to keep the tree protected.
When it comes to the fruit, temperatures reaching 26 to 28 degrees for more than two hours may begin to freeze and cause damage. Satsumas, navels, and Meyer lemon fruit have thinner skins compared to grapefruit and so are more likely to freeze. Ripe citrus fruit is more cold-tolerant than unripe fruit due to their sugar content. Unfortunately, if you have unripe fruit, remember that citrus does not ripen off the tree. If you notice frozen fruit after a freeze, salvage any fruit as soon as possible, mostly for juicing, or dispose of in the compost pile.
Citrus fruit showing damage after a freeze. Credit: Mongi Zekri, UF/IFAS
Now, back to the forecasters. They seem to get excited every time we begin to reach anywhere near 32 degrees and begin issuing frost and/or freeze warnings. These are important to consider, but as we now know, just because we’re getting frost or freeze temperatures, it doesn’t mean we’ll lose our citrus. According to the National Weather Service, here’s what all of these advisories mean:
Frost Advisory – minimum temperature is forecast to be 33 to 36 degrees on clear and calm nights during the growing season
Freeze Watch – issued when there is a potential for significant, widespread freezing temperatures (32 degrees and below) within the next 24-36 hours.
Freeze Warning – issued when significant, widespread freezing temperatures (32 degrees and below) are expected.
So, if you hear there is a frost advisory, not much need to worry. If we get all the way to a freeze warning, now we need to pay attention to what the minimum low temperature is forecasted to be. If it’s 28 or below, now we begin to worry about any fruit on the tree. It does have to hold at these low temperatures for several hours before damage occurs, so maybe we’ll be okay. Once we get to the lower 20s, we should probably go ahead pick all of the ripe fruit and hope for the best on any unripe fruit. At these sub-freezing temperatures, we also need to start implementing measures to protect the tree, especially the graft union where the top of the tree has been united with the rootstock, typically indicated by a thickened or swollen like area at the base of the tree. This includes tree covers and soil banking – mounding soil over the graft union through the sub-freezing temperatures.
When covering a tree for cold protection, be sure to drape the cover all the way to the ground. Credit: Jonathan Burns.
Another North Florida winter is here! With that comes a new plants from leafy greens to snapdragons. It also means the inevitable freeze is on the way. It is prudent for all gardeners to review what needs to be done to protect your non-freeze hardy plants.
Hardiness Zones
Before we get into what actions you may need to take, let’s examine plant hardiness zones. These are geographic areas created by the US Department of Agriculture defined by their average extreme minimal temperature. In the Panhandle these are zones 8b through 9b. In winter we will likely see low temps between 15 – 30 degrees depending on your zone. Sourcing plants appropriate for your zone can mitigate quite a bit of cold damage in your landscape. If you like plants susceptible to the cold, you can interplant them to add a little protection.
Microclimates
Find and utilize your yard’s microclimates. Areas under larger trees are likely to remain warmer in the winter. This is also true behind a windbreak, or near a structure with high sun exposure. Look around your yard and plant any cold sensitive plants in these areas.
This area is likely to have multiple microclimates. UF/IFAS Photo
Full Season Plant Care
Cold protection begins with warm season plant care. Pay close attention to the irrigation and fertilization needs of your landscape plants. Apply these properly to ensure stress free plants moving into the colder months as these will perform better as the mercury begins to drop.
Imminent Freeze Actions
Ok, now that everything is planned, we know our microclimates, and we’ve cared for our landscape through the year let’s see what can be done when a freeze is imminent.
Water the morning prior to a freeze event. Wet soils retain warmth better than dry. That heat will be re-radiated through the freezing night keeping your plant slightly warmer. Adding some mulch will aid this effort. Watering again the next day will break any ice formed in the soil. Keep in mind that prolonged saturation could be detrimental to root systems. Scout your plants regularly after using this strategy to ensure plant health.
Protect potted plants by bringing them indoors. Those that are too big to move should be padded with extra mulch, and clustered together when possible. Make sure to move them back in place when the warmth returns.
For those trees with graft points (i.e. Citrus), tree wraps may be used as protection. If you don’t have these, pile mulch around the base of the tree to insulate the graft. The idea here being that even if the branches above the graft succumb to the cold, the tree can rebranch above the graft thus keeping the desired fruit of that tree.
Finally, cover your plants. Covers are more useful for frost than freezing temps but are better than direct exposure to cold air. Keep these off the plant’s foliage while ensuring they reach all the way to the ground. Think ghosts over lollipops. Taking them to the ground will capture any heat radiated out of the soil overnight. The addition of lights underneath the cover can help keep that area a little warmer. Be very cautious when doing this as too much heat under the cover could be dangerous.
Plants covered above the foliage, and to the ground. UF/IFAS Photo
You may see some nurseries apply irrigation via sprinklers through the freeze as protection. While this method does work, it requires some specialty equipment. Additionally, you’ll need to apply the water prior to the freeze setting in and continue until the temps return. It not a practical solution for homeowners.
Once the cold passes, keep an eye on your plants. Wait until you see new growth before pruning damaged plant tissue. If in doubt you can slightly scrape the bark. If the cambium beneath the scrape is green, it is still alive.
For more information on cold protection or any other horticultural topic contact you local UF/IFAS Extension office.
Snowman in the Garden. Photo Credit: Abbey Smith, UF/IFAS Extension
2025 has already been a year for the books, as Winter Storm Enzo has proven that it really can snow in the Sunshine State. With the fluffy white snow also comes below freezing temperatures, therefore most landscape plants that fit the hardiness zones of Florida are not cold-tolerant or what is also called “cold-hardy.” In the Florida Panhandle, freezes are becoming more prevalent in recent years, so it is best to act ahead of time to protect your patio and landscape plants from feeling the adverse winter affects.
Preparation in Advance
Gardenia bush in the snow. Photo Credit: Abbey Smith, UF/IFAS Extension Jackson County
It is always best to do your research and know what hardiness zone(s) your plants will thrive in. This will help you understand the level of cold tolerance the plant can withstand and will allow you to select cold tolerant varieties that will grow best in the Florida Panhandle. You can find your hardiness zone by using this link: https://planthardiness.ars.usda.gov/.
Proper care throughout the year will also help your patio and porch plants withstand freezing temperatures; a healthy plant has a better chance of recovering from cold damage than an unmaintained one. A freeze event can usually be spotted in the forecast multiple days in advance, and it is best to be proactive by moving potted plants that would be adversely affected to the indoors or to a warmer sheltered area.
Cold Protection Tips
One of the most effective ways to protect your plants from cold weather is covering them up during the night. Frost cloths can be purchased at most garden stores or through online platforms. If you are unable to buy frost cloths, you can use breathable materials such as old bed sheets or burlap bags that will still allow for air flow to the plant but keep it insulated and warm.
Example of frost cloth protection. Photo Credit: Molly Jameson, UF/IFAS Extension Leon County
You can also use mulch for insulation. Applying a thick layer of mulch around the base of your landscape plants will help insulate the soil to regulate ground temperatures and protect the plant’s root system from cold weather damage. Pine straw or leaves will work best and should be applied in a 3-to-4-inch layer kept away from the base of your stem or trunk of the plant. In some cases, it may be necessary to use an outdoor heat lamp, but always ensure that it is placed away from any flammable materials and only used as needed.
It has been said that using your irrigation at home can be a form of freeze protection. This is typically not effective for a homeowner. When farmers run irrigation to protect their crop, the irrigation systems that are used commercially are designed for scenarios like this. The irrigation must be run for several hours after temperatures rise for this method to work and protect the plants. With a home irrigation system, this is considered water-wasteful and the amount of water a home irrigation system emits can turn into heavy ice quickly, which will damage your plant rather than offer protection.
Cold protection for plants in Northwest Florida is all about preparation. Whether its covering plants, adding mulch to your landscape, or moving your plants indoors, a little effort can go a long way in preventing cold damage. With a bit of TLC, you can keep your landscape and garden beautiful all year long.
Anchor frost cloth securely to keep it tightly in place, as removing air gaps helps trap ground heat and shield plants from cold air. Photo by Molly Jameson.
Here in North Florida, mild winters are the norm, but our occasional cold snaps can be enough to wreak havoc on our gardens. As you might remember, in December of 2022 the entire Panhandle experienced temperatures dipping into the teens and low 20s for several nights in a row, with some areas reaching as low as 18°F. This kind of unexpected freeze can catch even the most experienced gardeners off guard.
While plant covers are the go-to solution for many of us, pairing them with additional techniques can offer even better protection when temperatures dip. From common cold weather protection myths to practical DIY tips that enhance your plant cover’s effectiveness, knowing your options can make all the difference during an impending cold snap.
Cold Protection Myths and Misconceptions
When a frost or freeze warning hits, there’s plenty of advice flying around. Some of it’s helpful, and some, not so much. Here are a few misconceptions to clear up:
“Lollipop” trees will allow the heat from the ground to escape, giving the tree no cold protection. Photo by Jonathan Burns.
“It’s All About Covering the Leaves”
Many gardeners believe that simply covering the leaves of their plants will provide adequate protection. However, this can lead to what’s commonly referred to as “lollipop” trees, where only the foliage is covered, leaving the trunk exposed. This is problematic because cold air can still penetrate, and the heat rising from the ground isn’t captured effectively. To ensure proper protection, the plant cover should touch the ground all around the plant to trap heat radiating from the soil, providing insulation from below. For best results, choose a medium-weight frost cloth (about 1 to 1.5 oz/yd²) made from breathable polypropylene or polyester fabric. These materials offer excellent insulation, providing about 4 to 8 degrees of temperature protection, depending on factors like cloth weight, ground heat trapped, and wind conditions. Frost cloth also allows moisture and air exchange, which helps prevent overheating on sunny days.
“A Plastic Sheet Works Just as Well as Frost Cloth”
Throwing a plastic sheet over your plants might seem like an easy fix, but it often leads to more harm than good. Plastic is non-breathable, which can trap condensation and freeze on the plant’s surface. It also doesn’t insulate well, transferring cold temperatures directly to the leaves and stems. If you must use plastic in a pinch, make sure it doesn’t touch the plants directly and that it’s securely anchored to the ground to effectively trap warmth. Be sure to remove it in the morning once temperatures start to rise to avoid overheating.
“Covering Your Plants Alone is Enough”
With PVC hoops ready to hold frost cloth and a thick layer of pine straw mulch, these raised beds are prepped for whatever winter throws their way. Photo by Molly Jameson.
While covering plants is crucial, sometimes additional steps can make a big difference. Mulching around the base of plants with a thick layer of pine straw or leaves helps insulate the soil and trap ground heat. It’s a small step that offers big protection to the roots and lower stems.
“Watering Plants Before a Freeze Doesn’t Help”
Watering the soil around your plants before a freeze is a good practice because moist soil retains heat better than dry soil. This can help keep the root zone warmer overnight. However, it’s important to focus on watering the soil rather than the leaves. Water on foliage can freeze and cause damage, so it’s best to keep leaves dry as the temperatures drop. A deep watering a day or two before the cold hits is ideal for giving your plants a fighting chance.
DIY Cold Protection Solutions
If expensive greenhouses and plant covers are out of your budget or you want to get creative, there are plenty of do-it-yourself solutions for protecting your plants:
Recycled Materials as Frost Protection
Old bedsheets, towels, or even buckets and cardboard boxes can be used in a pinch to cover smaller plants. Just be sure to anchor them down well, so they don’t blow away.
DIY Hoop Houses
A temporary hoop house can be constructed using PVC pipes as the frame and polyethylene film as the covering to protect cold-sensitive plants during freezes. Photo by David W. Marshall.
For taller or sprawling plants, construct simple hoop houses using PVC piping with breathable frost cloth or lightweight plastic sheeting. Unlike placing plastic directly on plants, hoop houses create an air gap between the plastic and the plants, which helps trap heat from the soil while preventing direct contact damage. If using plastic, seal it tightly at night to trap warmth, and open it partially during the day to prevent overheating or excessive moisture buildup as temperatures rise. These low tunnels are perfect for garden beds or fruiting plants that need a little more room under cover.
String Lights for Added Warmth
For extra protection, consider using outdoor-rated incandescent string lights (not LEDs, which don’t produce heat). Drape the lights around or near the plant under the covering to create a gentle source of warmth, which can raise temperatures by a few degrees on especially cold nights. For fire safety, keep lights from direct contact with dry materials and use only moisture-safe, outdoor lights.
Windbreaks to Stop the Chill
In areas with open landscapes, cold winds can make frost damage even worse. Planting a hedge or using temporary barriers like hay bales or pallets can shield your garden from icy gusts and protect your more delicate plants.
One of the best ways to prepare for cold snaps is to plant cold-tolerant varieties suited to North Florida’s climate. Vegetables like collards, kale, and carrots, or perennials like rosemary and garlic chives, can withstand mild freezes with little effort. If you’re growing fruit trees, look for varieties with proven cold tolerance or dwarf varieties that are easier to cover.
With a little planning and a few simple techniques, you can protect your garden from unexpected cold spells and keep it thriving through our chilliest nights.
Freeze warning is a terrifying phrase for gardeners. Cold damages your plants and may even kill them outright. Understanding how plants freeze will help you create mitigating strategies for their preservation. Informing yourself as to how freeze damages plant tissues will allow you to fortify your garden.
How do Plants lose Heat
Cold exposure happens in a couple of ways. Radiant heat loss occurs when one surface emits waves of heat into a colder surrounding environment. The surfaces of leaves and stems are not immune to this type of temperature transfer, nor is the soil in your garden beds. Frost may or may not form depending on moisture levels in the air, but cold damage will still be the result. The other main source of heat loss in gardens is through Advective freezes. These occur when cold air from the north moves south en masse resulting in colder temperatures and often increased winds. Mitigating this is a little tougher than radiant losses but not impossible
IFAS Photo
As with all things, planning is at the forefront. When designing your garden, cold hardiness should be considered. Certain plants naturally handle cold weather better than others. Utilizing native plants and those specified for your USDA hardiness zone will keep gardens alive in winter months. These tend to be acclimated for colder temperatures. Once the proper plants are selected and planted, ensure they are properly treated. Keeping your plants as healthy as possible is also critical in cold tolerance. Mulches and watering prior to a freeze event will reduce risk from radiant heat loss. The water absorbs warmth through the day and holds onto it more efficiently than dry soil would. Addition of a frost blanket will further reduce heat lost and ultimately the damage to your plants. A slightly more in-depth protection method comes from establishing microclimates in your yard. Use taller trees and windbreaks. Taller trees create a canopy that blocks heat loss to the atmosphere. Windbreaks keep the colder air away from your gardens and again prevent heat loss. None of these methods are fool proof but will help keep your gardens alive through the colder months. You may still experience damage from freezes. If this does happen, make sure your plants are watered to thaw any roots ensuring they function properly. Inspect stems by scraping a little tissue. Prune away any that shows black or brown tissue while keeping any which still looks green.
IFAS Photo
Summing up
Freezes can be devastating to your gardens. A little knowledge can go a long way toward mitigating loss. For more information on cold protection, see this Ask IFAS document, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.
