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One of the biggest worries I have regarding my house plants is that they’ll get cold.
Since a lot of them hail from tropical rainforests and my house is very much not one of those, I’m constantly worrying that they’ll get cold. Not only do I live in the UK, famous for it’s cold and drizzly summers, but my house is super draughty.
I have an open fire, but whilst that would definitely warm things up, it’d also probably frazzle them. Hardly ideal.
I’ve now figured out where to put my most of my plants so that they’re warm enough, but not too warm, but also not sat in a draught. In winter, my medium-low light hallway is a no-go for most plants, but in summer it’s ok for hardier one such as Syngonium and Pothos.
Why do most indoor plants not like the cold?
Well for a start, it can kill them. Even outdoor plants die back in winter, unless they’ve evolved the wherewithal to survive it. Some plants can retreat back into their tubers, and then reappear in Spring, but most house plants are tropical, so haven’t developed the ability to do this.
A lot of plants practise consequential dormancy, which occurs when they sense winter coming, panic, and drop all of their leaves. Alocasia, in particular, do this, but I’ve successfully managed to keep mine undormant (?) so it’s not a forgone conclusion.
If you want to know more about plants going dormant and how to stop it, read this post.
Why do some plants like the cold?
I wouldn’t say that some plants actually like the cold, but a cold spell is a natural part of some plant’s life cycle, and they can’t complete it if there isn’t a drop in temperature.
For example, orchids appreciate a drop in temperature at night, as do string of pearls. But bear in mind we’re talking cool rather than cold.
As a general rule of thumb, few plants will tolerate temperatures below 7C/45F.
- There are some exceptions – many cactus species can tolerate sub-zero temperatures (Fahrenheit, which is -17C)
- ZZ plants can survive cold and low light conditions. What a champ
- Yucca can survive outside in winter (some can tolerate temps of -30), so they’ll be fine in your home. They do need a lot of light though, so they’re perfect for placing near french doors – a spot that’s too draughty for many plants.
- Maidenhair fern – whilst they’re very intolerant of many things (namely lack of water and humidity), they can survive sub-zero (F & C) without losing fronds.
Can plants get too hot?
Absolutely. In the rainforest it’s pretty hot and humid, but the humid environment and abundance of rain mens that it rarely gets baking hot.
Even if it did, the shade from the canopy and amount of damp leaf mould on the forest floor mean that a lot of plants aren’t equipped to deal with any extreme temperatures.
This doesn’t mean that you can’t take your plants outside in summer – you absolutely can, and it can really speed up your plant’s growth rate, BUT it’s not a case of just shifting your plants outside.
You must protect them from the sun and water the much more frequently – maybe even everyday depending on the plant, the potting mix and the material of the pot they’re in.
If you want to move your plants outside in the summer, then go ahead, but read this post first to avoid killing all your plants.
How to keep your plants warm enough in winter
Everyone tells you not to keep your plants near sources of heat, and largely I’d agree.
However, I have plants that live on a windowsill above a radiator and they’re fine – I think because it’s not a blast of hot air, but more of general heating of the surrounding air.
Honestly – my Fiddle-leaf fig is four inches away from a radiator and he’s doing great.
So my advice would be:
- Monitor plants that are near heat sources
Make sure they’re not drying out too quickly, or showing signs of scorching or lack of humidity.
Brown patches on the leaves and browning around the edges of the leaves are typical signs that your plant is suffering from dehydration. Also look for shrivelled and droopy leaves
- Keep your care on point
Your plant is much better equipped to handle cold spell if its other needs are met. Make sure it’s being properly watered, has adequate humidity, is kept clean, and isn’t infested with pests.
- Keep draughts to a minimum
Keep your doors and windows closed as much as you can.
In winter I move all the plants that I keep in my bathroom into another room, because if I don’t leave my bathroom window open for most of the day, mold appears.
Don’t compromise your health for your plants – just move them around so that you can keep them warm.
Even if, like me, you end up with an office that resembles a rainforest.
This can be beneficial to your plants, since grouping the together allows them to benefit from the humidity they create through transpiration, and they can create their own microclimate.
- Don’t repot in winter
I always used to say that you mustn’t fertilise your plants in winter, but that’s too general a rule – if your plant is growing and needs fertilising – fertilise it.
But I will stick by my advice not to repot in winter. If your plant is desperate and you can guarantee the plant will be kept warm, then maybe (before those of you that live in hot countries come for me), but in general, leave repotting for the growing season.
Repotting is stressful for plants – it’s not something they would ever encounter naturally, so they don’t really have a specific coping mechanism for it. If your plant is already stressed because its cold, repotting may be the final nail in its coffin.
I hope you found this helpful. If you live in a cold climate and constantly worry about your plants getting cold, get yourself cold hardy plants rather than bankrupting yourself by jacking up the heating.
If you need advice on how to successfully overwinter your house plants, I have a full guide here.