Deciding when to plant your garden can be a tricky business. Even when you’ve planned ahead, sometimes there’s a cold snap that comes late in the season and takes everyone by surprise. Plants you’ve painstakingly grown from seed and hardened off carefully can be endangered by cold temperatures and frost. Similarly, in the autumn, your harvest season can be interrupted by an unseasonal freeze.
What can you do to prevent cold damage to your tender plants and keep them healthy?
Tender, Hardy, & Semi-Hardy Plants
First, you need to know if your plants are tender. That means a plant that’s sensitive to freezing temperatures. A cold snap might only injure a tender plant, or it might completely kill it in a hard freeze.
If your plants are semi-hardy or hardy, they have some resistance to the cold and you don’t have to worry quite as much. However, some hardy plants can still be affected by cold temperatures by slowing their growth, especially as young plants. If that’s the case with your seedlings, you may still decide to protect them as if they were tender.
Protecting Container Gardens
If you’re growing a container garden, bring your plants indoors or move them to a sheltered spot to weather out the cold snap. If you don’t have the space to do this, then move your containers together to a sheltered spot near the house. You may also wrap the pots with blankets or plastic to insulate them from the worst of the cold. Container plants are actually much more susceptible to cold damage because they don’t have the protection of the ground to keep their roots warm.
Watering for Cold Protection
To protect your plants from cold weather or a freeze, water thoroughly the day before the freeze. This might be surprising, but wet soil holds the heat better than dry soil, and will help to absorb the radiant heat of the day. Skip this step for your succulents, which are more likely to be damaged if they are plump with water.
Mulch for Cold Protection
Mulch around the base of the plants heavily to help the soil you just watered to retain its warmth. If your soil drains too quickly, this keeps the soil moist as well as providing a layer of insulation. You can completely cover small plants with mulch to protect them, but be sure to uncover them in the daytime and when all danger has passed.
Cover your plants to protect them overnight. You can do this with bed linens, drop cloths, blankets, or plastic sheets. Anchor the cover carefully, so it doesn’t move around in the wind and harm your plants. Check for drafts or places the cold could seep in. Take care to keep plastic from touching the leaves of plants so that the plastic and leaves don’t freeze together and cause damage to the plant. Just like with mulching small plants, make sure you remove the cover during the daytime to prevent the plants from overheating.
Keep An Eye on the Weather
Of course, all of these steps require you to pay attention to the weather conditions during the changing seasons. We humans live in climate-controlled houses that always stay in a fairly consistent temperature range, and we can sometimes be a little bit oblivious to the weather. Stay on top of the weather. If you’re forgetful, it’s fairly easy to set up an alert to email you or text you in case of freezing temperatures. A little bit of proactivity goes a long way!
Winter Plant Protection - IFAS Extension
Five Ways to Protect Plants from Dipping Temperatures - USU Extension
Protecting Plants from Cold Temperatures - Mississippi State University Extension
Brrrr! How to Protect Plants from Frost or Freeze - IFAS Extension
Written by Teresa Chandler