Protecting Container Gardens from Frost

Move Plants Indoors

The simplest method is to move the containers indoors overnight and put them back out in the mid-morning when the air has warmed up again.  In the mid- and even late-fall, a garden shed or garage is enough shelter to keep your plants from freezing.  If they’re cold-hardy varieties, they won’t mind the nippy weather if they’re sheltered from it.  Warmer season plants like tomatoes, however, will need to be brought indoors to a warmer environment, such as your house, and will have to be kept indoors on cold days as well. 

Cold Frames

Another option is to build cold frames around the containers or that the containers can be set inside.  These are simple structures that look a lot like miniature greenhouses.  They will have four sides, be well-insulated from the outside, and usually have a glass or thick plastic top that can be exposed in the daytime to allow the inside to heat up from the sun using the greenhouse method.  These are sturdy little structures, but do not need to be permanent and can be purchased or built to be disassembled when not in use.

Make Your Own Covers

In the earlier week or two after the first frost, simple covers can be used to keep plants warm and frost-free overnight.  These can be large water-filled towers that are set around the plants to radiate daytime sun-heat onto the plants at night or they can be simple plastic frost covers available at most garden stores with heat stones set around the base of the plant to collect sunlight in the day and radiate heat overnight.

All of these methods work well until the weather turns for the worse and stays below 55 degrees Fahrenheit during most days.  At that point, more drastic methods will be required to continue extending the growing season. Read more about winter container gardening…