With winter well on the way, it's time to prep our precious indoor plants for the colder months to make sure they get through happy and thriving, not dead or barely surviving!
I remember my first 'winter with plants' when I had enough of a collection of valuable plants to worry about them making it through. Following these tips, I would have had nothing to worry about.
Well that's not quite true. If you know me, you know I worry a lot and love to plan ahead. So let's go with these prep steps meaning you'll have much less to worry about...
The #1 Killer of Houseplants in Winter
'Winter is Coming' doesn't immediately conjure up pictures of dragons, wolves and White Walkers like it used to when Game of Thrones was trending.
But I'm going to milk that Game of Thrones reference just a bit longer. Because winter is coming. And for the plant addicted, winter can be a little scary.
Summer is just SO easy. Often the biggest issue is just keeping up with watering the thirstiest chaps in the jungle, without going overboard and ending up with fungus gnats. Overwatering seems (almost) impossible.
As we slide into winter, root rot becomes a serious reality and the #1 killer of houseplants over the colder months. Overwatering is SO easy to do in winter. And overwatering can mean a swift death sentence compared to underwatering. Plus our plants can fool us into overwatering them if we don't know better.
But water's not the only winter worry. Here's what I do to get my indoor jungle prepped for winter, and what I've learned NOT to do as well, so they (and me too!), get through the colder months without the stress.
#1 Aziz, More Light!
(that reference is for you Fifth Element fans)
If you're lucky and get lots of light at your place, winter is wonderful. Instead of paranoid opening and closing of curtains and blinds to make sure no-one gets cooked, now you can chill. Although some (like me), do reply on grow lights to help get through the gloomier winter months.
Winter sun - even direct - is typically weaker than our intense summer sun. Some plants you would normally never dare place in the path of direct sun, can thrive over winter with a little sunbathing.
Great for a bit of sun stress (of the good kind), to colour up your plants too. Keep your Ficus Elastica Ruby red, and give your Tineke a soft blush. Keep Syngonium pink and Pink Bubbles from reverting.
Direct sun in winter is a necessity for most of your String-of and Chain-of everything's to get them through winter. Not for colour, but for survival. My String of Pearls HAVE to move to the windowsill for hours of direct winter sun a day to get enough direct rays not to go bald and slowly die off over winter at my place.
Most of our indoor plants need more light over winter, so even if direct sun is a no go, move your jungle closer to sources of light or grab a grow light.
Remember winter also means shorter days, so that means fewer daylight hours, so shift your plants in the best position to make the most of what they can get.
If you're worried it's still a bit low light to keep your jungle going, even with shifting them to new locations for winter, grab yourself a grow light for a few hours of extra light every day.
#2 Wipe Leaves
With more daylight hours and much brighter light in summer, a light coating of dust isn't too bad. Enough light can get through for plants to get by.
But come winter, those dusty leaves can cause health issues, attract pests, and when dealing with less light and drier air, clean leaves that can breathe and photosynthesize properly become even more important.
Grab a soft, damp cloth or (my favourite), dusting gloves, chuck something on Netflix to binge watch, and get wiping. It's very therapeutic. I use the Plant Runner Neem Oil Leaf Shine for mine, but after hearing fantastic feedback about the Forsana Foliage Magic that's in my cupboard for this year's winter prep.
Check first that your plant is oil-sensitive as both products include neem oil. I stay away from leaf shine products for all my furry-leafed friends with fuzzy or velvety leaves for example.
For sensitive plants without fuzzy leaves, a good tip is to 'wipe on, wipe off' (anyone else hearing Mr. Miyagi saying "wax on, wax off" right now?).
Spray your leaf shine onto a cloth or dusting gloves instead of directl on leaves and apply that way, then if needed, wipe off with a little plain water after. I do this for my orchids for example.
If you're not in the mood for a leaf-by-leaf wet wipe, chuck everyone in the shower for a good rinse, or get a spray mister out and banish those dust bunnies.
Remember even with a good shower rinse, dust can be pretty stubborn, so you will likely still need to wipe at least the newer leaves (who do a lot of the heavy lifting for photosynthesis).
#3 Don't Forget Your Windows
They might need a good spring clean too as part of your winter prep while you're in the cleaning mood (and if you feel like cleaning mine too, yes please, I never seem to be in this magical thing called 'cleaning mood').
#4 Keep it Warm
Most of the indoor plants we love come from tropical rainforest climates that stay warm, bright and humid all year round, with a 12 month growing season. Put them in a typical NZ house over winter and they may be missing home pretty fast :(
I use three temperature solutions for my plants. The first is I shift most of my more temperature sensitive houseplants into one room and pop an oil heater in the room, set to come on only when the temperature drops below 15.
For many houseplants, below 15 degrees Celsius (that's around 60 Fahrenheit), is the magic number where they start to struggle.
My second go-to for my baby plants and smaller temperature sensitive plants is to pop them in my Ikea cabinet (I have a Rudsta Wide). Even without weather stripping, my cabinet tends to stay a few degrees warmer than the ambient temperature, but if needed, I'll also pop a heat mat at the bottom to radiate up gentle, warmed air.
My third solution is also heat mats, just under my plant shelf where I house my larger more temperature sensitive plants. Heat mats are can be a very affordable, lower-cost, more area targeted way to keep plants toasty over winter.
If you get the type with a controller you can set the minimum temperature and leave it on 24/7 so it only comes on when the temperature drops, or just get a basic one that maintains the temperature 10 degrees or so above the room temperature. Inkbird makes both types.
#5 Move Away From the Window
Plants who thrived on windowsills during summer may need to be moved further away from the glass over winter, or at least over winter nights, as windows can be one of the coldest places in a home over winter.
#6 Watch out for Heat Pumps and Fireplaces
As well as shifting plants out of the path of cold drafts, watch out for warm drafts too, especially heat pumps, fireplaces and fan heaters. Set them further back than you might think otherwise leaves can quickly be scorched and die.
#7 Beware Dry Air
Many heat sources also dry the air. Humidity can drop down to 30% to 40% in a heated home over winter. Most houseplants originate from a tropical habitat where humidity is 70% to 80% even in the dry season!
HRV, DVS, air conditioning, heat pumps, fan heaters and fireplaces are all common culprits.
Watch out for the symptoms like slow death from the root tips inwards, starting with browning leaf tips and leaf edges, curling or cupping leaves and wrinkled, leathery-textured leaves.
The surface might be dry and leaves might be trying to convince you they are thirsty, but actually it's a dry air problem, and the roots are swimming in water.
Those signs that look like thirsty roots, could be a cry of attention trying to tell you humidity's too low. If you'd fallen for it and watered, you could easily lose your plant to root rot, when all they needed was humidity.
Used to high humidity all year-round in their natural climate, many indoor plants can really suffer over winter. Invest in a couple of humidifiers (I love the H2O portable cordless humidifiers).
Tip: Skip the pebble trays and misting
Misting and pebble trays barely make any difference to humidity over winter (or in summer for that matter). Misting may lift humidity for a couple of minutes, but not enough to make a difference.
Plus that water that stays sitting on leaves, stems and the crown of the plant can cause powdery mildew, fungal leaf spot and more in winter.
One tip I've seen shared elsewhere is to shift plants into the bathroom in winter for the extra humidity. But you can get the same problem happening. The humidiy boost is for too short a time make much difference.
Plus most bathrooms are designed to dry fast, and stay cooler and drier than the rest of your home. The opposite of what your plants want!
#8 Don't Buy a Humidifier
I know, I'm going against my own advice here, but I'm all for saving those plant pennies when you can.
Before you assume dry air is the problem and you invest in a humidifier, first get yourself a cheap hygrometer to keep an eye on the highs and lows to see if you actually need a humidifier.
#9 Don't Starve Indoor Plants in Winter
Many house plant hobbyists skip the fertiliser over winter. A habit that comes from our outdoor garden buddies.
I feed lightly right through winter. As I fertilise every time I water, my plants naturally get less food over winter because I water less frequently.
Feding over winter also helps prevent the usual yellow leaves that my plants used to get every spring like clockwork.
Here's why indoor plants need nutrients over winter > and also why plants get yellow leaves >
What I think you should skip over winter, is all the growth boosters. Think of them like your car's accelerator. Fertiliser is the fuel in the tank, and growth boosters are like putting your foot down on the accelerator.
Whether natural or synthetic, if you want to give your plants 'a rest' and can't provide the same warmth, light and humidity as spring and summer; winter's the time to ease up on the growth boosters, and cut back to just your essential plant fertiliser instead to get them through.
Or, if you want to keep using growth boosters over winter, like the amazing HB-101, definitely keep up the fertiliser, or the growth booster will deplete your plant's stores of nutrients faster than usual to fuel that fabulous growth, and you could end up with deficiencies come spring.
#10 Water Meters Save (plant) Lives
Before you water in winter, check the soil first and go deep! Get down as close to the roots as you can with the help of a water meter.
You may find your plant's only dry on the surface and the issue could be dry air, not dry roots. If you accidentally water when the roots are still wet further down, you could kill your plants.
Get yourself one of the types of soil testers that check moisture down at root level. Sustee are awesome if your budget allows (that's one shown in the photo below). They come in sizes for small up to extra large pots and change colour as the substrate dries down at the bottom of the pot.
The colour-changing PlantDoc are great for small to medium pots. They also change colour like Sustee, but are 100% plastic-free and fully biodegradable.
GrowProbe are a simpler, more budget friendly option also, great for deeper or larger pots.
Whatever you cann them - water meters, soil testers, moisture meters - they can be a total winter watering game changer and life saver to avoid root rot.
#11 How to Avoid Dry Rot
This one might be a no brainer for you, but in my books it's best never to assume what someone does and doesn't know.
Like washing hung out to dry in summer vs winter, everything stays wetter longer in winter, including your plant's soil.
Yes, plants need less water in winter. But that does not literally mean to give them less water! It means to water them less often.
When you do water, water heavily so no rots miss out. Giving them too little water by watering too lightly can cause root death from dry rot instead :(
#12 No Wet Feet
It's even more important to let plants fully drain in winter after watering, before putting them back in their cover pot. No wet feet!
Even for ones I'm chill about bottom-watering in summer, or watering in their cover pot and tipping excess out later when I remember, I get paranoid about over winter.
I still bottom water a lot of my collection in winter. But I set a timer so I don't go leave them to soak for too long, and so I remember to come back and tip out excess water from their saucers and cover pots later.
#13 DO Repot and Propagate
I know the advice is to never repot in winter and only propagate in spring and summer. I politely call BS on those 'rules'.
If a plant needs repotting for its health, any time of year, don't let winter stop you doing what's best for your plants.
I happily repot all year round. I just pop the plant on a heat mat in a bright spot (with a grow light if needed), for a speedy, problem-free recovery.
There's no reason you can't chop and prop your way through winter if you spoil your babies with a bit of extra heat, light and humidity afterwards, depending on their needs. That way they'll be ready for potting up come spring when the serious growth kicks in.
For faster rooting in winter so the stem doesn't rot before it's started growing roots, give fresh cuttings a dip in Clonex Gel. It not only gives them a dose of plant growth hormones but also helps seal and protect from root rot. You can use that in water or in solid substrates.
#14 Be on Pest Alert
The bad news is creating an ideal environment over winter for our indoor plants can also be heaven for bugs to thrive through winter too.
It's easy to assume winter means a break from pests, but it's not always the case for our indoir plants.
If you bring any of your outdoor plants inside for winter, keep them separate and watch for outdoor pests setting up home in your indoor plants. Quarantine your outdoor plants separately for at least 4 weeks (that's about the shortest period to covers the lifecycle of most pests), before they get too cosy with their always-indoor buddies.
Also keep inspecting your indoor babies for pests the same as you would over summer. Some like thrips love autumn, others like fungus gnats will cheerfully set up home in your plants all year round. Here's how to get rid of fungus gnats once and for all >
Winter schminter!
There you have it. 14 easy winter prep tips and tricks to get your precious indoor plants through winter safe and sound. If you found this helpful, please do give it a share. Shout outs much appreciated!
ABOUT THE AUTHOR: Anna is the owner of plant store Love That Leaf which specialises in products and advice for indoor plants. She is also the resident writer for NZ Gardener magazine on the topic of indoor plants. You'll see her houseplant care articles in magazines in-stores NZ-wide, and online on Stuff, The Post, NineHoney and more.