Preventing Frost and Freezing

3 Ways to Protect Your Plants Against Frost and Freezing

It’s winter and it’s been cold at night, which will keep happening for a while longer. The problem is that our plants are made for hot dry weather, they don’t do well in cold weather. So, what’s the problem? Frost and freezing.


Frost is caused by temperature and moisture combining, like dew, then solidifying in crystals on your plants. Think of the way a glass of ice water left to sit will pull moisture from the air to the outside of the glass where it will condense, it’s like that, except that it’s cold enough outside that the condensation freezes. That is different than the plant itself freezing…


Freezing is more like what happens when you put a glass of water into the freezer. When the temperature drops below 32 degrees (freezing). Plants are full of moisture, trunk, and leaf, the different types of plants have different types of sap that freeze at different temperatures, some slightly lower than freezing. When the plants freeze on the inside it damages them, killing sections of the plant that were too far from the warmer core of the plant. If the plant isn’t hardy enough, the entire plant could die.


The best way to avoid killing off your garden is to insulate the trees, bushes, and flowers. Here are your options:

  1. Cloth: This is usually the best option, especially for the canopy or foliage of a plant. This isn’t the kind of thing that can be tarped over the top and tied off at the trunk or stalk, that’s not how it works. The cloth needs to extend all the way to the ground, if that means using more than one piece, then do it. This technique depends on the heat escaping from the ground as the ground cools down, you need to trap all of that heat around each plant, like a tent to keep it warm. It’s most effective if you do it late in the afternoon, before it starts cooling down and leave it on until late in the morning, to allow the ground to heat up again before repeating the process. You can amplify the effect by placing a low-wattage lamp inside the “tent” as well, nothing that will get too hot and become a hazard.
  2. Paper: Paper, or cardboard is a great way to wrap the trunks of small trees to add extra protection to them, but it’s not going to do anything for small plants or even the leaves of the tree it’s wrapped around.
  3. Plastic: Do Not Use Plastic! It’s true that the using a plastic tarp can be used to protect against frost, letting it collect on the plastic instead of the leaves of your plants. But plastic doesn’t make a good insulator, during the daylight, it can allow heat to pass through while keeping out the elements. After the sun goes down though, it doesn’t do anything to keep warm air in or cold air out. One plastic technique that will keep them warm is wrapping the trunk of your tree with incandescent Christmas lights, the heat will keep them warm. Warning- LED Christmas lights WON’T WORK! Because they don’t use a filament, they don’t produce heat and therefore won’t protect your plants.

As long as this weather keeps up, it’s a good idea to keep an eye on it, and check nighttime temperatures and dew points. Keep your sheets handy, and get an early start before the ground gets too cold. If you’ve already experienced some frost damage, it is OK to prune the dead wood, but be sure to leave about 3/4 inch of “dead” wood to protect the “live wood”. If you need a little help keeping it Green, our passion is more than just growing – It’s keeping your landscape investment healthy for years to come.