Few gardeners have not inadvertently exposed a chilly plant to the cold. Perhaps, like you, we were busy at the end of summer. Or out of the area when there was an early frost. Or (and this has happened to me more than once), we thought we had brought all our plants inside, only to realize after the frost hit that one or two were still out in the open.
And sometimes frost damage can occur inside the home. If the heat is missing in the winter and the situation persists for several days, the temperature can drop below 32°F in even the best insulated home.
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How to save a frozen houseplant?
Has your houseplant frozen? The reason is simple: it is because you placed it too close to a window or a bay window. However, some varieties do not tolerate negative temperatures, and even less the frost. The latter can pass through windows and fall on green plants which suffer from it.
The result: the leaves of your aloe vera or orchid become soft and yellow. But don’t panic: there are a few solutions to save a frozen houseplant: follow our slideshow carefully to learn more!
How to take care of houseplants in winter?
Indoor plants need to be pampered in winter. Thus, watering is less important than in summer, so moderate watering: once or twice a week is enough. To create a humid climate, group your plants together and mist their foliage.
Also, make sure to place your plants in the right place in your home: do not place them next to the heating or a fireplace, as this could dry them out. When it’s freezing, avoid placing them near a window, and beware of draughts in the entrance!
Which plants are less resistant to frost?
All plants are different when it comes to temperature and hardiness. Some plants will not survive snowy spells and falling temperatures. This is the case for aloe vera, cactus, hydrangea, orchid or azalea.
Why is frost fatal for indoor plants?
Frost can be fatal for some houseplants. Leaves may start to soften, petals may fall off, flowers may wilt and die… As soon as you start to observe a plant suffering, it is essential to act and save it.
How to protect your houseplant from frost?
To protect your houseplant from frost, it is best to prepare for the arrival of winter beforehand and put it in a dry and bright place. But be careful not to place it too close to a window. You can also put a winter veil on the subject (especially for potted citrus).
How to water when it freezes?
Is it necessary to water in winter when it freezes? It depends: if the substrate is very dry, water in small doses. Above all, don’t forget to mist the foliage to keep it moist!
Frost damage
Frost causes devastating damage to plant cells. When water freezes, it expands, bursting the cells. Then, when temperatures warm up again, those cells suffer further damage from dehydration. The young cells are the most fragile, and so the young leaves and also the flowers and flower buds are the most damaged.
More mature cells can tolerate a little more cold, or at least longer periods of cold. The cold passes through thin stems quickly, but takes longer to penetrate thicker stems… and the bark, if any, also provides some insulation.
For these reasons, when the plant survives the frost, the parts least affected tend to be those inside the branch (thus less exposed to the wind), the oldest branches… and the base of the plant.
Houseplants that have the ability to regenerate from their base, roots or underground rhizomes, bulbs or tubers are the most likely to recover from frost. Potting soil tends to retain heat and the larger the pot and the larger the potting soil mass, the better the insulation. It may take several cold nights in a row before the potting soil freezes completely.
It is the tip and the edge of the leaves that are most susceptible to frost, then the rest of the leaf blade. The veins, being thicker, are better insulated and often stay green longer but, if the frost persists, eventually the whole leaf will succumb, becoming brown or black and soggy.
Sometimes it falls off, sometimes it dries out. Flowers and flower buds react in the same way. The leaves on the inner part of the plant may remain intact, especially if there was little wind. Non-woody stems turn brown or black when they freeze and may curl, soften or even collapse; those that are more woody may show no signs of damage other than leaf drop.
Not everything may be lost
Don’t automatically give up on a houseplant, even one that has been seriously damaged by frost. There may be dormant buds still alive under the bark or at or below ground level.
Recovery can be slow, however: it may take several months for growth to resume and, depending on the species, the plant may take years to regain its original size. You need to decide whether you are willing to wait or prefer to start over with new plants.
If any of your houseplants have suffered frost damage, bring them in to the heat as soon as possible. Don’t worry about acclimatization: it’s already in shock and needs first aid instead. Acclimatization will come later.
Cut off damaged leaves and any obviously dead growth. If it is a shrub, you might as well prune it severely, shortening the trunk and the main branches: this will give it a denser future appearance… if it recovers.
