If you own an orchard, there’s no doubt that you have a pretty good idea of what frost is doing to plants. But for many people who might not work with plants professionally, it’s not so obvious as to what exactly is happening to a plant when it is damaged or killed by temperatures that get too cold.

For many parts of the country, the first frost has already hit. But there are many parts of the South that still haven’t seen their first frost yet and might still be in need of frost protection like frost covers and frost blankets. And when spring comes around, planting plants early can also make them susceptible to the last frost. If you’re wondering how to protect plants from frost, here are some examples of what you’re protecting them from and what you can do about it.

(FYI: Technically, there is a difference between a freeze and frost. But since most gardeners use them interchangeably, we will too for the purposes of this article.)

Know Your Frosts

DId you know that there are actually two different types of frost? Well now you do!

First of all there is air frost. Air frost occurs when the air temperature reaches 32-degree Fahrenheit, aka 0-degrees celsius. This is most likely to affect thin branches, leaves and flowers.

Second, there’s ground frost. As you probably know, the temperature of the ground stays constant the deeper you go. At 30 feet down, the temperature is the same year-round. At 15-feet down, the ground temperature is about six months behind the air temperature, and at 5-feet down it’s about 3 months behind the air temperature. But roots of new plants don’t go down much further than a couple feet, meaning that ground temperature is going to affect them and their water transporting abilities.

Water Expands

One of the most interesting facts that most of us learn in grade school science is that water is the only substance on Earth that expands both when it’s heated and when it’s cooled. That’s what’s going on with the plant cells and why they can die during a frost.

Each plant cell contains water. When the water freezes and expands, it can burst the cell. Not only that, but the ice crystals that form can shred the plant’s cells.

How Does Damage Occur?

Let’s take a quick look at why and how damage occurs:

Leaves and Flowers — When you touch a tree or a plant, the most easily-damaged parts are the leaves and the flowers. While you might have to use force to break a branch, the leaves and flowers can be torn with almost no effort. Because of their thin nature, there’s almost no insulation in a leaf or flower; freezing temperatures have an immediate effect on them.

Branches — How branches are affected often has to do with what type of plant we’re talking about. Most of us know that a tomato plant’s branches are almost as susceptible to the cold as its leaves are. Tree branches, on the other hand, are less likely to suffer damage. But new trees, especially those out in the open, can be damaged if their bark is too thin and the cold gets to their water-filled living cells.

Roots — We don’t have to tell you that the roots of the plant are vitally important. Unfortunately, exposed roots mean that they are more likely to freeze or be dried out by the wind.

Another common reason that roots of a plant are affected is soil heaving. This occurs when the freeze/thaw cycles pushes roots up and out of the ground, exposing them to the elements. In order to prevent this, add more soil, mulch, or shredded leaves.

So, How Do You Protect Plants From Frost?

Natural Protection — Every plant has a different method of dealing with frost. Take tomato plants and begonias, for instance. How do they deal with frost? They just die and don’t have to worry about it any longer! Classic tomato…

Other forms of natural protections include bark (insulation), sugar and aminos acids (which create a type of antifreeze), and cell drainage (where arctic plants remove the water from their cells so that it doesn’t freeze. Kinda like blowing out a sprinkler system!).

Plant Covers and Blankets — Most of the damage that garden plants suffer is due to air frost. Plant covers help the plant keep the warmth that it received from the sun during the day from going away too quickly. Frost blankets can keep the warmth that the ground absorbed from the sun close to the plant. Both of these methods can also protect the plants from wind, which carries away warm air and also dehydrates the plants.

The best way to protect your plants is by picking plants that are right for your part of the country and by purchasing some frost protection from Frostproof Growers Supply. Get ready to plant early in spring by grabbing some today!