Freeze Damage on Plants

Freeze Damage on Plants

I moved my pothos closer to the window last January because I thought it needed more light. Three days later, half the leaves looked like wet tissue paper. That’s when I learned that cold glass and houseplants don’t mix, especially during a polar vortex.

If you’re reading this because your plant touched a frozen window or sat too close to a drafty door, I’m sorry. It’s frustrating. But most plants can bounce back from cold damage if you catch it early and don’t panic-prune everything immediately.

Identifying cold damage

The tricky thing about freeze damage is that it doesn’t always show up right away. Sometimes you wake up, see your plant looking fine, and then two days later it looks like it went through a blender.

Cold-damaged leaves usually turn dark and mushy. The cell walls inside the leaf actually burst when ice crystals form, which is why the texture changes so dramatically. You might see black or brown spots first, or the whole leaf might go translucent and soggy. It’s different from the crispy brown edges you get from underwatering. This is wet damage.

According to researchers at the University of Minnesota Extension, temperatures below 50°F can damage tropical houseplants, and anything near freezing will cause cell death in most common indoor plants. I didn’t believe this until I left a fern on my enclosed porch overnight when it was 45°F outside. The fronds turned brown within 48 hours.

Sometimes the damage is subtler. You might notice leaves drooping more than usual, or they feel limp even though the soil is properly watered. The stems can also get soft and discolored near the top. If your plant was touching a cold window, check the leaves that were closest to the glass first. Those are usually the ones that got hit hardest.

One thing I’ve learned from forums and my own mistakes is that cold damage can look a lot like overwatering at first. Both cause mushy, darkened tissue. The difference is where it happens. Cold damage usually affects the parts of the plant closest to the cold source (a window, a door, an AC vent). Overwatering typically starts with the lower leaves and works its way up.

You should also check the stems. Gently squeeze them near the soil line and work your way up. If they feel firm, that’s good. If they’re squishy like a rotten banana, that section is gone. I had to toss a whole tradescantia last winter because the cold snap turned the main stems to mush at the base, and there was no saving it.

Pruning mushy leaves

Here’s where I messed up with my pothos: I immediately cut off every damaged leaf the morning I found them. Don’t do that.

Wait at least a week, maybe two. I know it’s ugly. I know you want to fix it. But the plant is already stressed, and cutting away a bunch of leaves (even damaged ones) is additional stress. The plant might also be able to salvage some of those leaves if the damage isn’t too severe.

After about a week, you’ll have a clearer picture of what’s actually dead. Some leaves that looked questionable might perk up a bit. Others will get progressively worse and start to smell weird. Those are the ones you remove.

When you do prune, use clean scissors or pruning shears. I wipe mine down with rubbing alcohol between cuts, especially if I’m working on multiple plants. Cut the leaf stem (the petiole) as close to the main stem as possible without damaging the main stem itself. If an entire stem section is damaged, trace it back to healthy tissue and cut just above a node if you can.

I learned from a horticulture blog called The Sill that you should avoid removing more than 30% of the plant’s foliage at once, even if it’s damaged. The remaining leaves (even the ugly ones) are still doing some photosynthesis and helping the plant recover. If more than a third of your plant is damaged, remove the worst offenders first, wait another week or two, then reassess.

For stems that are mushy, cut them back to firm tissue. If the mushiness goes all the way to the soil, you might be able to save the plant by propagating any healthy growth that remains. I had to do this with a coleus last year. The cold killed everything except the top three inches of one stem, so I cut that section off, stuck it in water, and got a new plant out of the disaster.

Don’t try to peel off damaged parts of leaves that are otherwise healthy. I tried this once with a monstera that had cold spots along the edges. I thought I could just trim the brown parts and leave the green. It looked terrible, the leaf died anyway, and I should have just removed the whole thing.

Above: A close up look at the symptoms.

Recovery timeline

This is the part nobody wants to hear: it takes a long time.

Most houseplants won’t show significant new growth for at least a month after cold damage, sometimes longer. They’re putting energy into repairing root function and recovering from the shock. You won’t see new leaves popping out right away, and that’s normal.

According to research from the University of Florida’s Environmental Horticulture Department, plants that experience cold damage need to rebuild their vascular systems before they can support new growth. The damaged tissue can block water and nutrient transport, so the plant has to work around those blockages or grow new pathways. This takes time.

In my experience, fast-growing plants like pothos and philodendrons will start pushing out new growth within four to six weeks if the damage wasn’t too severe. Slower growers like snake plants or ZZ plants might not show visible recovery for two or three months. I had a snake plant that sat near a cold window for one night, lost two leaves to mush, and didn’t produce a new leaf for five months. It eventually recovered, but I had pretty much given up on it by that point.

The recovery timeline also depends on the season. If your plant gets freeze damage in February, it’s going to recover slower than if the same thing happens in May. Most houseplants naturally slow down in winter anyway because of lower light levels and shorter days. Adding cold stress on top of that means they’re really not in a hurry to do anything.

Some plants won’t recover at all. If the cold killed the growing points (the newest shoots at the tips of stems), the plant might survive but stay stunted. I had this happen with a basil plant. It lived, but it never got bushy again because the main stems stopped growing after the freeze.

You’ll know your plant is actually recovering when you see firm new growth emerging from the nodes or the center of the plant. The new leaves should look normal in color and texture. If new growth comes in pale or deformed, something else might be wrong (usually a nutrient issue or pest problem).

Prevention tips

I moved all my plants at least three feet away from windows after the pothos incident. Even windows that don’t feel cold to your hand can create a microclimate that’s much colder than the rest of the room, especially at night.

If you have plants that need bright light and must be near a window, check the temperature at plant level with a basic thermometer. I bought a cheap indoor/outdoor thermometer and stuck the outdoor probe right next to my plants for a few nights. I was shocked to find that the spot where my fern sat dropped to 52°F at night even though my thermostat said the room was 68°F. The glass was sucking all the heat away.

Curtains or blinds help, but you have to close them before the sun goes down. The glass gets coldest in the early morning hours, so leaving curtains open overnight defeats the purpose. I close my blinds around 4 PM in winter, which feels ridiculously early but keeps my plants safer.

Draft detection is harder. I found most of my drafts by holding a lit incense stick near doors, windows, and baseboards. If the smoke suddenly moves, there’s a draft. My front door was leaking cold air so badly that my umbrella plant (schefflera) started dropping leaves even though it was six feet away. I had to stuff a draft stopper under the door.

The University of Georgia Extension recommends grouping plants together in winter because they create a slightly more humid and stable microclimate. I’ve noticed my plants do seem happier when they’re clustered versus spread around the room, though this might also be because I water them more consistently when they’re all in one spot.

Don’t put plants near heating vents either. I know this article is about freeze damage, but blasts of hot, dry air are just as bad in the opposite direction. I killed a prayer plant this way before I understood what I was doing.

If you know a cold snap is coming and you can’t move your plants away from windows, you can insulate them temporarily. I’ve used cardboard, bubble wrap, and even moving blankets as barriers between plants and cold glass. It looks stupid, but it works for short-term emergencies.

Above: The tools you need to fix this.

Moving plants from drafts

Okay, so you found the draft or the cold window. Now you need to move your plant, but you also don’t want to stress it more by changing its light conditions drastically.

If possible, move the plant to a spot with similar light levels that’s just farther from the cold source. My pothos went from right against the east window to about four feet back from the same window. Still got morning light, just without the freezing glass contact.

When you have no choice but to change the light situation (like moving a plant away from the only bright window in your apartment), do it gradually if you can. I know this sounds impossible if your plant is actively freezing, but for milder situations where you’re just eliminating a draft, try moving the plant a foot or two every few days rather than relocating it all at once.

After moving any plant, don’t change anything else for at least two weeks. Don’t repot it, don’t fertilize it, don’t even change your watering schedule. One stressor at a time. I made the mistake of moving my cold-damaged pothos AND repotting it the same week because I convinced myself that fresh soil would help it recover. It went into shock and dropped even more leaves.

Some plants really hate being moved and will throw a fit even when you’re trying to save them. Ficus trees are notorious for this. I don’t own one specifically because my apartment is too dark and I know I’d have to keep moving it around to find the right spot. But I’ve read enough stories from other plant people to know that ficus will drop leaves if you so much as rotate the pot.

Watch your plant for the next few weeks after moving it. If it starts developing different problems (like stretching toward light, or getting crispy leaves from too much sun), you might need to adjust again. There’s no perfect formula. Every apartment has different light, different drafts, and different warm spots.

I’ve also learned that sometimes the best spot in winter is not the best spot in summer. I have a shelf that’s perfect for low-light plants in December but turns into a solar oven by June. I end up shuffling plants around seasonally, which is annoying but better than constantly dealing with temperature damage.

The goal is to find a location where the temperature stays between 60°F and 75°F consistently, with no sudden cold drafts and no blasts from heating systems. For most rooms, that’s somewhere in the middle, away from exterior walls and windows. Not exciting, not Instagrammable, but safe.

I hope your plant makes it. Check back in a month and see if there’s new growth. And maybe invest in that cheap thermometer. It’s helped me more than any fancy gadget I’ve bought for my plants.

References

University of Minnesota Extension. “Protecting Houseplants from Cold Damage.” Extension.umn.edu. Retrieved from university horticulture resources on cold tolerance in tropical plants.

University of Florida Environmental Horticulture Department. “Cold Damage and Recovery in Ornamental Plants.” Research publications on plant vascular recovery following freeze events.

University of Georgia Extension. “Winter Care for Houseplants.” Guidelines on temperature management and microclimate creation for indoor plants.

The Sill. “How to Prune Houseplants After Damage.” Hobbyist blog entry on recovery pruning techniques and timing.