Philodendron Burle Marx new leaf in a lime green, photo taken from aerial view focusing on the leaf and showing part of the pot and soil with the text "HOW TO PREP YOUR HOUSEPLANTS FOR WINTER"

How To Prep Your Houseplants For Winter & Prevent Chill Shock

This summer has been an absolute scorcher – I’m sure it came as quite a shock to many of us in the UK, when we’ve come to expect our summer months to be filled with wind, rain, and disappointing temperatures (with the occasional bit of sun). But this year my house was reaching 28C downstairs and up to 32C you can imagine, there were a few plant casualties!
Logically, based on the current evidence of climate change, it would be expected that an abnormally hot summer would be followed by an abnormally cold and harsh winter. With the cost of living crisis being a living nightmare for most of us at the moment, the prospect of having to spend ridiculous costs on heating just for ourselves is difficult (and we certainly don’t need to be making that cost any more extortionate by worrying about heating plants). When we saw the projections for our winter energy bill, I immediately started to panic about my more rare and sensitive plants...if we can’t afford to heat ourselves, we can’t afford to heat the plants! So, I’ve started to think of some reasonable solutions that can be implemented to prevent a winter-based plant extinction for anyone in a similar situation to my household.
This is going to be based on the premise that you too, like me, will either: 1) Not be heating your house using your boiler or an electric heater this winter 2) Only be heating one room in the house if the temperature is below liveable for us even with blankets – i.e. below 0C.

Avoid Storing Plants In Lofts and Places With Drafts

A lot of us have entire spaces in our houses dedicated to plant-care. Personally, I have an overflow of plants in my loft for when there’s no space left in my greenhouses, bedroom, or humidity bins. The problem with a loft room is that it’s poorly insulated, as they’re designed for storage as opposed to actual living. The fact that it was so much hotter in there reinforces the importance of insulation in maintaining constant temperatures – in Winter, this problem is mirrored, and the room can’t retain heat on its own (last year I used a greenhouse heater upstairs, which melted to the plug socket and almost set on fire and is also too expensive to use this year). So, now that you have about a month to prepare for low temperatures, it’s the time to start thinking about how you can change your setup to avoid leaving plants in a poorly insulated room. You’ll also want to avoid placing sensitive plants close to windows in any room, and completely avoid having leaves touch the glass of your windows as it gets very cold. If you have grow lights, I would move all of your plants off the windowsill and use the artificial light source (more on that later).

Try To Move Plants Into One Or Two Rooms In Your House

 In case you have to put the heating on, it’s best to have all of your plants in one room if possible, as it will help maintain warmth and also because you only have to pay to heat one room rather than the whole house. I recommend turning off the radiators in all the other rooms (like actually turning them off at the valve so that water doesn’t enter them whatsoever, not just having it on 0 as that won’t make as much of a difference as actually disconnecting them for the winter). Definitely spray with Provanto or Neem Oil before moving all your plants in together, even as a preventative if you don’t see any pests. It’s best to pick the room that you’re going to be spending the most time in (ideally your bedroom, because if you have to heat yourself one night to avoid freezing to death, at least the plants can benefit from the same heat).
Group Plants Together Where Possible
 By ‘group plants’ I mean literally push them close together as this helps keep the plants better insulated and will also help with providing a higher humidity. Definitely pest check or preventatively pest treat before doing this, because if there’s a pest problem then unknowingly grouping an infested plant in with the others could cause a full-on pest outbreak in your collection. To prevent pest transmission, I keep plants in categories and group based on area. So this year, in my bedroom the groups will be: Greenhouse 1, Greenhouse 2, Humidity Bin 1, Humidity Bin 2, Humidity Bin 3, Sideboard (and all the rest that are currently dotted about and on the windowsill will be moved to the sideboard).
This also helps you to save money on electricity, as having your plants grouped together means that you can use the minimum amount of grow lights. I will be attempting to reduce my grow light use to just one for this winter. It is pretty important to supplement natural light in this time anyway because it’s massively reduced in comparison to summer, but it is essential to provide high-light-requiring plants (e.g. cacti, succulents) with a grow light if you’re moving them away from the windowsills. Even the low-quality grow lights emit a small amount of heat, so it will (albeit minorly) contribute to the temperature stability we’re after.

Use Bubble Wrap To Further Insulate Planty Spaces

 I will be wrapping my greenhouses in additional bubble wrap to further insulate it (obviously don’t cover the zips). I’m going to be layering it around the sides and the back, then I’ll make a separate lot of layers for the front panel (I will make a blog post on this when I do it). I will also be wrapping around the sides of groups of plants (e.g. my sideboard will be full of plants pushed together, and the bubble wrap will be layered loosely underneath and around the sides of the plants and pots, leaving the top open so the leaves can still take in light. This will also allow me to lift out a plant when it needs watering.

If You Have An Indoor Greenhouse, Use It

 Whether it’s a basic plastic greenhouse that you’re using indoors, a grow tent, or even the beloved IKEA cabinet, all of these things will help to keep the plants free from draft and will most likely be the hottest area in your house (especially if you’re using grow lights) so I recommend putting as much as your collection as you can into anything like this. Even cupboards will help to insulate the plants (depending on their position in relation to grow lights/windows) as long as they at least have a glass door to allow the amount of light the plant requires to pass through. It’s also easier to insulate a greenhouse with bubble wrap (as mentioned above) and to use the last-resort heating methods (see final step) when your plants are more fully contained.

Cover Windows With This Insulating Plastic 

I found this stuff last year, and while it is a total eye sore, it makes a big difference. The plastic adheres to your windows and the gaps between the windows/walls where drafts pass through. It helps the temperature remain higher for longer and prevents drastic temperature change caused by cold winds – ideal for the UK winter. I will be using this in my bedroom and leaving it in place until late spring.

Keep Doors Closed Whenever Possible

 For both humidity and temperature maintenance, you want to keep all your internal and external doors shut wherever possible, as the door being open allows all the humidity and warmth to escape and for cold, dry air to enter. Every time you open the door to your plant room or greenhouse, you want to make sure you’re opening it for as short a time as possible and closing it after yourself. If you’ve got kids in the house, now is the time to teach them that it’s important to close doors.

Buy Some Temperature Gauges To Help You Out

There are these awesome two-in-one temperature and humidity gauges I’ve been using for ages, and the thing I love about them is that they use a solar powered battery. I think I paid about £7.00 for a set of three, and I’ll be getting some more before Winter so that I can closely watch the temperature for each group of plants in my bedroom. You’ll also be able to monitor any sudden changes much more efficiently and rectify the situation (hopefully) with some of my suggestions.
(I think these are the ones I use, but a lot of them look similar) LINK:

 Last Resort Save For Extreme Temps...

So you’ve done everything I recommended, but it’s a really cold day and the temperature isn’t looking great in your planty spaces...As a last resort, I recommend using either hot water bottles or a heat-up bag (the microwavable wheat bags) and putting it in the bottom shelf of your greenhouse so that the heat will rise up and heat the whole greenhouse. BUT when you do this never put the plants on top of the heat source because it’s going to be too hot initially and cook the roots (i.e. don’t use the bottom shelf for plants if you’re using it for heating). If you don’t have a greenhouse, you can also place a hot water bottle of the surface your plants are standing on (e.g. my wooden sideboard that has a lot of plants heats up really well like that, I just put the bottle on the sideboard and it heats the whole thing up).
Best of luck on your winter plant parenting journey – it can be a challenge, but it’s all worth it to see our beautiful plants thriving again in spring.
- Sofi
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