Many homeowners worry about just how to protect their plants from the coming cold weather. The anxiety may be more deeply felt in places where there is a long growing season and frosts arrive late. The homeowner may have planted a garden full of summer vegetables that are still bearing, for example, and a sudden frost could mean a loss of tomatoes, okra, eggplant or warm season herbs such as basil.
Why is Cold So Harmful?
Frost hurts plants because it sets up ice crystals in their cells, which blocks nutrients. Because of this, the plant’s leaves turn black, shrivel up and fall. If the ground itself freezes, the roots have trouble getting nutrients up into the plant. A cold wind and bright sun can cause the plant to dry out. The good news is that there are ways to protect a plant that is tender to frost. Here are some of them:
1) To best protect them, plants should be placed in the right area. This means that frost tender plants should not be placed out in the open or in dips in the ground where cold air accumulates. The best place is against a wall with a southern or western exposure or around protective shrubs, fences or other hardscaping. These structures take in the sun’s heat all day and releases it at night. This is one of the reasons that it is good to grow plants, even vegetables, in pots. They are also easy to move from a cold area to a warmer one. Being grown in pots is especially useful for succulents.
2) Make sure that the plant is well watered before a cold snap. This may seem counterintuitive, but soil that is wet retains heat and keeps the air around the roots and the bottom of the plant warm. Cover the soil with mulch to help it retain the water. The one caveat is that this shouldn’t be done with succulents, which store water in their leaves. The soil that succulents grow in needs to be kept dry during a cold spell. If the ground is too wet, the leaves may burst in the cold.
3) Another way to protect plants is to carefully drive in stakes around the plant and cover them with fabric. Make sure the fabric doesn’t touch the plant. Take the covers down in the morning when the temperature starts to rise. If the gardener feels they need to keep the plant covered for a while, they should choose a fabric that allows light and air to get through to the plant.
4) If the plants are still seedlings or tender ground covers, fork some straw or mulch over them. Make sure to carefully rake off the covering when the temperature warms.
5) Put outdoor, old-fashioned incandescent lighting around the plants. Do not use halogen lights because they are too hot, and do not use CFLs or LEDs because they are too cool. Make sure the light is not touching anything, especially the plant.
6) Some plants benefit from being sprayed with an anti-transpirant, which helps to lock in moisture by coating the leaves with polymer. This can help a plant get through a few weeks of moderately cold weather.