If you live in one of California’s micro climates with cold winters, you’re familiar with the regimen of moving potted plants indoors before the first frost. If you live in an area with mild winters, the occasional frosty night can still wreak havoc on plants, especially potted ones, which are more susceptible to cold weather. Incorporate one or more proactive measures to protect your potted plants from frost damage.

• Water the potted plants the morning before frost is expected. Well-watered plants are less susceptible to frost damage.
•  Move potted plants indoors or into a garage or outbuilding. You can also put them on an enclosed porch. You can do this just for the night or for the few days when frost is an issue.
•  Apply mulch on top of the soil, up to the rims of the pots. This will insulate the soil and protect the roots. You can also wrap blankets, bubble wrap or burlap around the outside of the containers for extra insulation. If you have extra mulch, surround the containers with it. In autumn, fallen leaves provide abundant and easy-to-use insulating mulch.
•  Place the open side of cardboard boxes up and over the pots, making sure they are large enough that they don’t touch the foliage. Cover the plants in the evening and take the boxes off in the morning after the air has warmed. Another simple way to cover plants is to put a chair over the pots. Drape a sheet or burlap over the chair until it touches the ground on all sides. You can also use buckets, milk jugs with the bottoms cut off or larger plant pots.
•  Gather potted plants together and place them close to each other. Do this in front of a wall or under an overhang on the warmer southern or western side of the house. The wall and overhang provide some cold protection and the grouped plants have greater thermal mass and help each other stay warm. Place your most cold-hardy plants on the outside of the group and the tenderest plants in the middle.

Things You Will Need

• Mulch
• Blanket, bubble wrap or burlap
• Cardboard box, bucket, milk jugs or plant pots

Tip

• Take note of the temperatures in your yard, particularly in the areas you have potted plants. Compare this information with the weather report to give you a more accurate picture of the weather in your landscape. This information will help you know when you should protect your potted plants.

References

• University of California: Coping With Winter
• Sunset: Protect Plants From Frost