If you don’t live in an area where it is frost-free year-round, you need to plan for your plants for wintertime, states Tammy Sons, a gardener at Tn Nursery.
Frost and hard freezes are detrimental, usually deadly, for most plants. Frost is traditionally categorized one of two ways:
Why is Frost Harmful to Plants?
Frost and freezing injuries plants because plants are mostly water; plants can be up to 95% water.
When the water inside plants turns to ice crystals, the tissue is damaged, and the movement of fluids and nutrients within the plant is disrupted or completely halted.
Water Plants in the Afternoon
This is less about hydrating the plant and more about moistening the surrounding soil around it.
Wet soil has an insulating effect, meaning that heat from the ground will radiate upwards to the plant overnight when the temperatures are most likely to drop.
Add a Layer of Mulch to the Plant
Thick mulch to a plant is what a heavy quilt is to a person. Use mulch to insulate the plant. The best method is bagged mulch, sawdust, woodchips, straw, grass clippings, or even leaves as protective mulch. Add three to six inches of your mulch around each plant and leave one to two inches of space between the plant’s main stem and the mulch. This allows the earth’s warmth to slowly radiate up past the fragile plant as the temperatures drop.
When the weather begins to warm, pull some of the mulch away.
Use a Cloche to Cover the Plant
A cloche is like a miniature greenhouse.
It is a bell-shaped cover that is somewhat or entirely transparent, made of plastic or glass, and intended to retain heat or humidity for individual plants.
You may purchase cloches online or from your local nursery. You may also make some at home using regular household items.
You can repurpose buckets, flowerpots, cups, and jars into cloches. Many people prefer plastic jugs and bottles as cloches because the cap can be added or removed as needed for heat and humidity fluctuations. Milk jugs and pop bottles with the bottoms cut out are also practical.
For maximum effect, screw the cap on tightly, add to the plant just before dusk, and nestle the bottom of the cloche firmly into the soil. Be sure to uncover the plant at dawn so the plant can soak up the sunshine and warmth of the morning right away.
Use Rocks and Bricks as Miniature Heaters
During the warmest part of the day, place a rock, brick, or chunk of concrete beside your plant.
While it is sunny and warm, it will absorb heat. Slowly overnight, it will release the heat. If you place it next to your plant, it can act as a small heater.
If you really want the maximum effect, utilize a warming rock and a cloche. Allow the stone to heat up in direct sunlight all day, and then cover the rock and the plant with the cloche right at nightfall.
Blanket Your Fragile Plants
For plants that need protection from winter freezes, consider using burlap, blankets, towels, or drop cloths. The blanket method is like the cloche method but on a bigger scale.
Create a tent-like structure using t-posts, tomato cages, stakes, or even chairs so that the material doesn’t crush the plants. Make sure your fabric drapes all the way to the ground, and don’t tie it to the trees or plants. The earth’s heat to radiate through the plant and hover within the tent-like structure you created.
Weigh the edge down with rocks or stake it down so it doesn’t blow away overnight.
For additional frost resistance, you may add a shower liner, a sheet of plastic, or a tarp to the top of the blanket.
Ensure that no part of the plastic touches your plants as it can harm the foliage.
Just like the cloche, add the blanket right before dusk, and remove it again at dawn.
This tip seems counterintuitive, but I assure you, it is effective. The secret is that the constant airflow blows away lingering precipitation that may lead to damaging ice or frost.
Surprisingly enough, simulating wind can raise the temperature of your garden patch by anywhere from 2°F to 7°F degrees.
Bring (or Keep) Your Plants in a Temperature Controlled Building
A greenhouse is the absolute best way to protect and overwinter even the most fragile plants.
Greenhouses retain heat from the sun naturally. They can also have electric heaters, woodstoves, or geothermal heat sources installed into them as well. Greenhouses come in various sizes and can range from tiny three-square feet all the way up to two-hundred thousand square feet. There are thousands of options and price points to choose from.
If a greenhouse isn’t feasible for you, consider keeping your beloved fragile plants in pots. When the weather drops, you may bring them inside your home to protect them from the brutal cold.
If you plan on taking your plants in and out of your home, consider using a preventative anti-bug measure such as neem oil. Neem oil acts as an insecticide and a miticide, which will protect you, your home, and your other indoor plants from pests.