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I’ve only been into keeping house plants properly since about April of this year, so all the information in this post is from Google, not from experience.
Also, I know it doesn’t really need to be said but this post isn’t for those of you that live in countries where the temperature doesn’t dip below 15 degrees (centigrade – I have no idea about Farenheight).
Your plants will be fine.
I live in the north of the UK. It gets…pretty cold.
We don’t really get into minus temperatures very often or for very long (whilst climate change behaves itself anyway), but it’s certainly not rainforest-balmy year-round. Or ever.
Do house plants go dormant?
The answer to this is: some do. Some don’t. Some do a bit. Depends on the conditions and the plant. I wrote an article about it here.
There is a lot of talk about plants going into dormancy over the winter months, and whilst it’s true that the growth rate of plants slows down considerably, that doesn’t mean that your plants can withstand anything and don’t need the occasional drink of water or ray of sunlight.
Your plants aren’t hibernating. They’re just doing the best they can in suboptimal conditions. I have compiled a list of points that you should really consider if you’re interested in keeping your plants as happy as possible until the Spring.
Positioning
Winter is a bit of a catch 22 for house plants. They get less light (as, you know, the sun goes home pretty sharpish in winter) so they want to be closer to the window, but if they’re close to the window then they might catch a chill.
I’d definitely advise against keeping plants off windowsills over which you’re planning to draw your curtains. One of the reasons curtains are effective at keeping out the cold is that they trap cold air between the curtain and the glass.
Not many of your house plants will enjoy that in winter.
I currently only have cacti and succulents on my living room windowsill sill – they are more than happy to tolerate extreme cold (as long as they don’t get wet) because the desert environments they inhabit in the wild get very cold at night.
***My cacti flowered! Clearly they like the drop in temperature***
Some people even keep succulents outside all winter – as long as they don’t get rained on, they’ll be fine, so you could keep them under a porch or something.
So yeah, if possible, move your plants so that they’ll be on the good side of the curtains.
If you have a spare room with a decent window that you can set them all up in they’ll like that. I took my pans off my open shelving in the kitchen and put a lot of my plants on those.
They’re only a few feet away from a south-facing window so FINGERS CROSSED they’ll like it there.
In short, you need to keep your plants away from cold spots and draughts. They won’t like that at all.
Getting adequate light for your plants when the days are short
I honestly think that this is the thing I’m going to struggle with most. It shouldn’t be too difficult to install a few strips of grow lights on the shelving, but I’d rather save the electricity. We’ll just have to see how they get on.
UPDATE (Dec 2020) – I’ve found AWESOME grow lights (actually aquarium lights), and I’ve done a whole article about them. Everything you ever wanted to know about grow lights.
I don’t think I have too many plants that need bright light – my philodendron and calathea should be ok, since they don’t mind medium light and they’re quite close to the window.
I have a south-facing bathroom window, but the only plant in there at the moment is a maidenhair fern. Bathrooms, in general, are a bit too cold for plants in winter, and since I like to keep the bathroom window open almost all day to prevent mould growth, it’s not the best environment for plants.
Signs that your plant is getting inadequate light:
- Slow growth (although growth is slower in winter)
- Pale or small leaves
- Long gaps between leaves
- Excessive leaning towards the sun.
If you think your plant is showing any or all of these symptoms, then it probably isn’t getting enough light. Either try moving it to a brighter position or invest in some grow lights.
Keeping up the humidity in the colder months
Central heating can play havoc with humidity – not only does it reduce it, but it can make humidity peak and trough and your plants may not appreciate that.
If you struggle with maintaining humidity in winter and you have a lot of plants that need high humidity, I would recommend you invest in a humidifier.
If you have the funds, invest in one that you can set to come on and go off when the desired humidity is reached. Not only will this keep your plants happier, but it’ll also mean you can have a more hands-off approach. If you’re a fan of the hands-off approach, get a humidifier with a large water capacity so it doesn’t need filling up so often.
If you want to keep up a heavy (but cheap) misting schedule, that’s fine, but the amount this actually changes the humidity around the plant is a topic of hot debate in house plant circles.
As you may know from reading my other articles, the humidity in my house runs at a whopping 65%. Great for my plants, not great for people that don’t want to spend their mornings squeegeeing the windows and wiping the walls of the bathroom.
I’m actually excited – I’ve lived in this house for two years, and have gotten used to my squeegeeing and opening windows routine. The fact my plants love it is just a bonus to me.
You can get those little diffusers for home use which will do in a pinch for very dry homes but bear in mind that the cheaper ones don’t allow you to program them and they tend to only have a small water capacity. If you’re happy to stick to operating it manually and fill it up then it’s far better than misting.
You can get in between humidifiers that can be controlled by Alexa. That’d be a good option.
If you have a lot of plants, a dry house and no funds for a humidifier, put all your plants together in one place. Plants release water from their leaves. Another plant can then absorb that water. Voila – you’ve created your own little microclimate.
Hell, you can even mist them if it makes you feel better.
*** HUMIDITY LIFE HACK*** if like me you have a tiny house with tiny rooms, air-drying your clothes near your plants can increase humidity by about 10%. Nice.
What’s the optimal temperature over winter?
Optimal? Like, 20 degrees, but that won’t happen without some serious reduction in humidity unless you have a sauna.
House plants don’t much like to go below 17 degrees (excluding desert plants which can go down to minus figures). This information is unwelcome to me because I have a cold house (if you hadn’t already guessed, it’s an old house). They really don’t like to go below 10 degrees, but they may have to just try.
However, I’m unwilling to get into debt by heating my house to high heaven, plus that’d compromise my fucking ON POINT humidity. So I’ve put all the plants that don’t like drafts and like a bright light in my spare room.
The room is tiny and has a radiator and a big window. My fiddle leaf fig SEEMS to be happy in there, but who can tell? It’s currently putting out three leaves (show off) so its windowsill position seems to suit it.
Since it’s the spare room, we’re not going to be closing the curtains on an evening. I’m not sure what the humidity’s like there, so the calathea and ferns are all staying in the kitchen. I have one monstera in the kitchen and one in the spare room, so I’ll do an update in the spring about which did best (I ended up making them roommates in the same pot in the spare room).
The living room will be fairly dark in winter, and the curtains will be closed. The only plants staying in there will be pothos and philodendron, plus the cacti and succulents on the windowsill.
If you put your heating on more to combat the cold air, be aware that that will compromise the humidity.
Oh, and fluctuations in temperature are just as bad for plants as prolonged hot or cold spells so try to keep temperatures evenish. Just do what you can. All we can do is our best.
Please god I hope my plants survive.
Watering over winter
You still need to water all of your plants in winter, but since the plants are growing much more slowly and the sun isn’t around as much to evaporate the water, you will need to water far less often.
A moisture metre will be indispensable in winter (it is to me year-round) because plants are more susceptible to root rot in winter.
Also, due to central heating, the surface of the soil may dry out pretty quickly, whilst the rest of the soil is bog-like. Don’t rely on your finger (or eyes) to determine if a plant needs watering.
Be sure to use either room temperature or tepid water. Cold water will shock the roots, and we need to keep the roots as happy and healthy as we can. If you’re watering on the fly and don’t have any room temperature water to spare, then boil some up in the kettle to bring it up to room temperature (or even a touch warmer, but never hot).
Some plants, like cacti and succulents, may not need watering at all over winter. Don’t worry about it – they’re literally designed to hold onto water. Just check them regularly and if they need watering, water them. If they don’t, leave them alone.
Ok, update time. It’s February now, and I don’t think I’ve been watering that much less. Cacti have been bone dry after about a month, so don’t bargain on just abandoning them until spring.
Pest control during winter
You need to be vigilant about checking for insects and diseases in winter – the plant will be in a weakened state and will succumb to infestation and infection much quicker.
I would recommend bottom watering in winter. If the top layer of soil remains dry, then it’s a pretty inhospitable environment for bugs. Most house plant pests thrive in damp, dank environments, so denying them that will make them less likely to set up camp.
I would recommend staying on top of dusting your plants so that any potential pest threats can be sorted out early. A quick dust and polish with neem oil will help to keep bugs at bay without resorting to any harsh insecticides.
If your plants are already attracting a lot of bugs such as fungus gnats, then try to suppress them before winter. Add a layer of pebbles or sand to the top of your pots so that they can’t lay their eggs and any larvae can’t get out. This can also provide a layer to help keep the plants warm.
Fertiliser (or lack of) in winter
Don’t fertilise your plants in winter. They won’t use it since they’re not growing, and you can actually harm them.
Ok, experience Caroline is editing this section.
You don’t need to fertilise your plants in winter, but you can if they’re still growing. If you’re unsure, top dress your pots with some worm castings.
They don’t contain any super potent chemicals, so won’t damage the roots of your plants but they add a bit of nourishment to the soil.
Fertilisers can cause the roots of your plants to burn, and again, we need our roots to stay strong and healthy. Forget about fertilising until the spring unless you have plants that you know are actively growing and need it.
Keep to a schedule, even in winter
It’s so easy to forget about your plants all winter since they don’t really do anything.
One of the things that make looking over my plants so exciting is seeing all the new growth they’re putting out. It can be a bit disheartening in winter when they’re not doing…anything.
Turns out that isn’t an issue – in the middle of winter some of my plants are growing happily.
Think of it like this though – the better care you take of your plants over the winter, the quicker they’ll be able to get into the swing of the new growing season come spring. They won’t need any time to recover or grow stronger roots.
Make a point of checking all of your plants once a week. Check that they’re not thirsty, that they’re fairly dust-free and make sure that there are no signs of any unwanted beasties.
That’s it.
It needn’t take long.
(Unless, like me, you have waaaay too many plants).
Put a reminder in your phone or on your calendar or whatever.
In conclusion
Winter can be a very stressful time for house plants that would really prefer to be in the rainforest. They don’t require much in the way of care over winter – the most important thing you can do is keep a regular eye on them.
Oh, and don’t stress them out further, unnecessarily.
That means don’t take cuttings (they’d be unlikely to root in the cold and dark, anyway), don’t move them around constantly, don’t overwater them, and don’t re-pot them.
Buy some winter plants if you need to mother something. There are loads of options, and a lot of plants that grow in winter have flowers, which is cool.
Oh, and funny story. One of the first house plants I bought this year was a cyclamen. It was blooming when I bought it and when it went into dormancy I carefully trimmed back all the dead foliage and did the whole laying-the-bulb-on-its-side thing that you’re meant to do. I kept it watered (but not wet) all summer despite feeling like a fool for watering what looked to be an empty pot.
When it came to moving it downstairs to shine in my living room all winter, I couldn’t find the bulb. I searched all through the soil, but couldn’t find anything. The thing had completely disintegrated. To the point where you couldn’t even begin to tell that it wasn’t just pure potting mix. Did the bulb jump out and run away??
Disappointing.
Anyway, cyclamen are pretty so I’m going to get another. I’m also excited to get a Christmas cactus and a Poinsetta.
My experience of keeping 100 house plants alive over winter in the UK
It was…fine.
I didn’t really fertilise my plants, and a few are still putting out new growth. I’ve had no insect infestations (though I’ve been trying to be better about dusting the leaves, so the neem oil is hopefully doing its thing).
I’ve lost a few leaves due to the cold I think. I have a neon pothos that isn’t looking so hot, but the only plant I’ve lost is a calathea medallion my rabbit ate, and a baby syngonium that got obliterated by aphids.
The aphids are living on my string of pearls, and I can’t seem to shake them. Every time I get rid of them, more show up. The string of pearls is ok though, so I just make sure to check my other plants a lot.
