How to Protect Plants from Frost

All gardeners know that we may have consequences for anything we do ahead of schedule. Yesterday it was in the low 80s, today it’s the low 60s, and now we might be looking at frost over the weekend. So, all those tender seedlings we optimistically transplanted are at risk. Yours, too? 

To protect plants from frost, start by identifying tender plants that need covering or a sheltered place before temperatures fall.

How Frost and Freezing Affect Tender Plants

While light freezes usually don’t do too much harm, deep freezes can cause the cells within your plants to burst causing severe damage to your plant’s foliage and killing its blooms. Plants will also die from desiccation (drying out) which occurs when the plant can’t process enough water. The cold winds can cause a plant to dry out, so it is still important to water plants in cold weather.

For a closer look at freeze damage and differences in plant cold tolerance, read how to protect plants from freezing

Most annual plants and vegetables weren’t meant to survive freezing and frigid temperatures, so one way to protect them is to move them into a warmer area if possible. An area such as the garden shed or garage is perfect for container plants and annuals as they usually remain a few degrees warmer than the outdoors. They don’t need the super-warm conditions of the house, which can make re-acclimatizing outdoors more difficult. If you have transplants in the middle of the hardening off process, bring them indoors at night and outdoors during the day until the temperature rises above freezing at night.

How to Cover Plants for Frost

There are excellent frost protection supplies you can get, and we highly recommend the Easy Tunnel and insulating plant protectors for both spring and fall crops. But for right now, rely on the tried-and-true home remedies:

Cover tender plants with frost cloth or an old sheet before sunset, extending the cover to the ground. Use supports where needed to keep heavy fabric off delicate plants. Remove temporary sheets when temperatures rise above freezing. Follow the manufacturer's directions for purpose-made frost cloth. Remember to lift them when the temperature rises above freezing, though, because they don’t admit as much light and air (and almost no water) as plants need.

Move Potted Plants to Shelter

Move potted plants to a frost-free location, such as the garden shed or garage. If possible, just get them a few degrees above the outside temperature, they don’t need the super-warm conditions of the house, which can make re-acclimatizing outdoors more difficult.

Check soil moisture before the cold arrives. If the soil is dry, water while temperatures are above freezing; avoid waterlogging. Moist soil holds more heat than dry soil. Spraying foliage during a freeze is a separate technique that requires continuous irrigation and is not recommended here for home gardeners.