Raised garden bed covered with frost cloth, anchored securely with firewood along the edges to prevent air gaps, helping to trap ground heat and protect plants from cold air.

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:

Potted tree covered with frost cloth, tied securely around the trunk, with the cloth extending only around the foliage, resembling a 'lollipop' shape

“Lollipop” trees will allow the heat from the ground to escape, giving the tree no cold protection. Photo by Jonathan Burns.

  1. “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.
  2. “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.
  3. “Covering Your Plants Alone is Enough”
    Raised garden beds framed by cinder blocks with PVC hoops installed over plants, and pine straw mulch covering the soil.

    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.

  4. “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.

    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.

Long-term Planning: Choose Cold-Tolerant Varieties

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.