Protecting Your Plant Pots in Winter
If you live in a colder area, some of your garden's plant containers may not make it through the cold winter. Some containers will do fine outside on the balcony, but many materials will absorb water, which will freeze and expand. Then the plant container will become brittle and crack, break or flake. Keep your brittle plant containers indoors or purchase containers that will overwinter well without any extra precautions. If you live in an area that doesn’t drop below freezing (or below 40 degrees for a long period of time), you won’t have to worry about overwintering your plant containers.
Plant Container to Bring Inside
Terra cotta
Glass
Glazed pots
Plant Pots That Can Be Left Outside
Styrofoam
Plastic
Polyurethane
Fiberglass
Wood
Hypertufa
Concrete
In the plant containers listed above, you should plant your cold-hardy container plants that will stay outside during the winter. For annuals, the more brittle glazed containers and terra cotta pots can be used, and then stored indoors in the off-season.
If you have a space to store your containers complete with the potting soil inside them, then bring them inside. You can keep the potting soil in the containers and reuse it next year. (If you’ve had a plant disease outbreak, you may want to sterilize the soil and plant containers before reusing them.) If you don’t have space indoors, you can take precautions to keep the containers from breaking by wrapping them up in bubble wrap. Wrapping them in bubble wrap will lower the chances of your containers breaking, but it is not always 100 percent effective.
The best thing to do is to purchase containers that are safe to keep outdoors all winter (this way you can create interesting winter plant displays). Apartment-dwellers generally do not have a lot of space or a garage where they can keep plant containers during the winter. So when purchasing your garden's plant containers, choose plant pots that can be left outdoors.