What to Do if Your Plants are Exposed to an Unexpected Cold Snap

updated Jan 10, 2024
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window sil full of fake plants
Credit: Sarah Crowley

No surprise here: When it comes to weather, most indoor and outdoor plants prefer the hot days of summer to the cold chill of winter. But sometimes things happen — like an unexpected (and unprecedented) winter storm, a mail-order plant that was left out on the porch for too long, or even just a planter left by an especially drafty window. So can you save your plants after a frost or cold snap? You might think that plants that have been exposed to extreme cold are goners, but there are a few steps you can take that might help revive your struggling greenery.

Of course, the best method for saving plants from frost or extreme cold is to implement preventative measures. For houseplants, make sure your windows are sealed and you’ve moved all your plants away from chilly drafts and the cold window panes. Also, keep those houseplants away from doors that open to the outside.

For your outdoor gardens, add extra mulch around perennials and consider using frost cloth if the forecast is looking unfavorable for sensitive plants in your agricultural zone.  

If your plants have already been exposed to cold temperatures, there could still be hope. The following tips might not prove successful in every scenario, but it’s a good place to start. Here’s are the best methods to try to save plants after a frost or cold snap.

Quick Overview

How to Save Plants After Cold Damage

Move houseplants to a warmer area, then water. Make sure to skip fertilizer until the plant is fully recovered. For garden plants, give them a little recovery time before attempting anything. Protect delicate plants with frost cloth in case of continued cold temperatures. Don’t fertilize until the plants are fully recovered.

Signs Plants Are Too Cold

The first step in knowing how to help your plants is being able to identify whether or not conditions have been too frigid. “House plants carry the name house plant, but most are actually tropical plants, which means their climate doesn’t freeze,” says Master Gardener David Angelov.

He also suggests using your senses to gauge if the temperature may be too chilly for your plants because it may be a few days before foliage starts to show signs of cold-induced damage. “Generally, if you need a sweater, it’s marginal, and if you need gloves, it’s way too cold,” advises Angelov. 

Common sense goes a long way in determining whether you need to move your plant or not. However, houseplants — normally tropical species that reside outdoors in warm climates — will show signs of freezing. “Frost-bitten tropicals will show signs of mushy or crinkly leaves and a darker/faded color leaf,” adds Angelov.

What to Do for Cold-Exposed Houseplants 

You have to remember that most common houseplants are tropical, and a lot of them are extremely sensitive to temperatures under 50 degrees Fahrenheit. 

Some houseplants will start dying the second the temps dip, but others can regenerate from healthy roots below the soil even if the top part of the plant is completely frozen.

An important factor in the chance of survival is how long the plants were exposed to cold temperatures. A few hours can do the job, depending on the plant. Generally, though, it takes 12 to 24 hours of exposure to cold temperatures to completely kill most tropical plant species. 

If you’re in doubt about whether a plant survived, check the roots. If they’re white and firm, you’re good to go. If they’re mushy, your plant won’t be able to make a comeback. The roots may also be somewhere in between — and if that’s the case, you should give revival a chance with the following tips for saving plants after a frost or cold snap.

1. Get the plant to warmer temperatures as soon as you can.

Bring the plant into a warmer area as soon as possible. Don’t go about cutting off any foliage that looks dead — simply concentrate on getting the plant warm.

The recovery process will start (depending on the length of cold exposure) as soon as the plant warms up. Don’t try to accelerate the process by placing it on a radiator or heating element. Let it happen naturally.

2. Water right away.

Give the plant a small amount of water right away and let it drain out of the container.

When plants freeze, the moisture gets sucked from the leaf tissue — which is a huge problem because plants need hydration in order to live.

As the plant tries to recover, water as you normally would.

3. Skip fertilizer.

Do not fertilize. You risk damaging the plant tissues during this recovery phase. Instead, leave your plant to recover alone.

4. Later, prune dead foliage.

Cut off all dead blooms and foliage, but not until after the plant has been “warm” for at least a month. The plant needs time to regenerate energy, so give it some space. 

Credit: Ivan Hunter | Getty Images

What to Do for Cold-Exposed Outdoor Gardens

Unlike houseplants, outdoor gardens are typically planted with zone-appropriate plants that have a good chance of recovering from a brutal cold snap, so trust your local nursery’s selections. “Many plants are tolerant of the cold, and most garden centers and landscapers plant what is correct for the climate,” says Angelov.

After the temperature drops to 32 degrees Fahrenheit and lower, frost forms on the ground from water vapor that has condensed and frozen. As the cold air hits the leaves of actively growing plants, the water inside the leaves freezes — just like with houseplants. This damages the plant cells and, therefore, damages the plant.

You’ll be able to tell when your garden is suffering after a cold snap. Leaves will curl, drop, or change color — usually from green to white, yellow, black, or brown. Here’s what to do to try to maximize recovery for your outdoor plants after cold damage.

1. Leave the plants be… for now.

At first, leave your plants alone.

It can be very, very tempting to run out after the frost or snow melts off your garden. In general, it can be hard to see what damage has been done until the plants try to generate new growth.

You’ll find that snow is a good insulator from extremely cold temps — and sometimes it can work in your favor.

2. Bring potted plants inside.

If you have potted plants outdoors, bring them inside and follow the directions for the houseplants, above. 

3. Protect sensitive plants.

If the forecast calls for more cold temps, it’s a good idea to try to protect sensitive plants with frost cloth to prevent more damage. 

4. After things warm up, get back to normal.

Once the temperatures warm, begin your typical watering routine. Just like tropical houseplants, outdoor garden plants need water to begin the regeneration process.

5. Don’t fertilize.

As with tropical houseplants, do not fertilize until the plant has fully recovered. 

Unfortunately, you’ll know if they’re completely dead if you leave them alone for a month or two and they do not begin to show signs of new growth.

With plants, you win some and you lose some in the long run. The longer you garden or keep a houseplant collection, the more you’ll learn — but there’s always room for the unexpected! Following these tips will help you save what you can.

How to Know if a Cold-Exposed Plant Can Be Saved or Not 

If you trim your semi-frozen plants back properly — which involves removing spent leaves and leaving more than two-thirds of each original leaf — Angelov says they should begin to sprout again. “Remember, plants are living, ever-changing organisms and want to grow,” he says. “It’s in their genes.”

Basically, if you start to see new sprouts in a few months, your plant is set to survive. Unfortunately, if you don’t see any new growth, the plant most likely won’t recover from freezing. “It most likely will be fine with some proper rejuvenation if not left out for the whole winter,” says Angelov. 

One final word of advice: Don’t overwater a heavily pruned plant. “Fewer leaves means the less water the plant can take up, which means you need to water it less,” Angelov says. Although it may be tempting to overcompensate with extra water and fertilizer, small steps are best to help your plant recover.