How to help houseplants over the winter blues

With a few exceptions, January is a trying time for houseplants, but the best cure is prevention. By Alice Vincent

I’d be amazed if you didn’t have a dying houseplant somewhere in your home. As I write, I can see a selfpitying gangly Begonia maculata ‘Wightii’ and Calathea roseopicta (rose painted calathea) consisting of three crispy leaves. The ZZ plant (Zamioculcas zamiifolia), pushed as close to the window as possible, is putting on a brave face and the philodendron is fine, if in a bit of a grump. The vast majority of houseplants suffer from winter blues as much as we do.

There are a few exceptions: the Christmas cactus (Schlumbergera), tends to explode in a riot of colour around now (often pink, just to clash nicely with the decorations) and there’s usually a rebel – one winter my maidenhair fern decided, like Robbie Williams, that December was the time for a surprise comeback. But mostly it’s a time of crispy leaves, slow-to-non-existent growth and at least a little soilsurface white mould.

The causes are simple: most houseplants are, in origin, tropical species used to warmer, more humid climes with plenty of sunlight. The growing period for most of them has also come to an end. It’s a double whammy of conditions making it difficult for the mature plant to survive, and little to no new growth to replace what doesn’t.

Central heating dries out the air, causing leaves to crisp and turn brown; longer nights mean the plant has to struggle for more daylight; gloomier conditions and plant dormancy leads to soil that stays soggy, causing plant rot and whitefly.

Knowing the cause is half the battle. The best cure is prevention: astute houseplant carers will have stopped watering and feeding weeks ago and shuffled plants around into the light.

For future reference, I tend to rely on the clocks going back as a marker of plant winter slowdown (and when clocks go forward again, I take it as the return of the growing season, more for ease of remembering than scientific certainty). Until then, here is the need-to-know:

SHUFFLE THEM ALL ABOUT

Your houseplant may look charming tucked away on a bookshelf during spring and summer, but keeping it so far from a light source during the dark months could be lethal. Give them a chance and move plants as close to windows as possible. This does, however, come with some caveats: a cold draught can kill overnight, while perching a plant over a radiator will induce a slow and crispy death, so keep them away from both. If you have underfloor heating, raise plants on to a table.

CUT BACK ON WATERING

Overly soggy soil can be a killer at this time of year: stem rot, mouldy soil, fungus gnats, the lot. While you should always be checking soil before watering (stick a finger in up to the knuckle; if it feels dry and crumbly, it’s time to water), if you do it now you’ll note that the soil stays damper for longer.

Which means larger breaks between watering: two weeks at the least, as a rough guide. Some of my succulents and more drought-friendly plants, such as the jumbo Ficus elastica (rubber plant) in the bedroom, will get three big drinks between now and March, if they’re lucky.

Be vigilant about draining run-off water out of cachepots.

BUT KEEP AN EYE ON HUMIDITY

The jury on misting is still out, depending on which houseplant aficionado you talk to, but I’d be wary of covering leaves in a fine dew without adequate natural warmth or light to absorb it. Instead, I support humidity-lovers by creating little reservoirs: saucers with gravel and a splash of water underneath pots do the job nicely.

NO NEED TO FEED

Plants will hardly be growing at the moment, so you’ll just be wasting the feed and it can damage roots. Hold off until spring.

BE PATIENT WITH PROPAGATING

I’m itching to hack back at the aforementioned begonia, but it would be pointless: most cuttings would take an age to root in autumn and winter. Best to let it do its leggy best until spring and then give it a good haircut.

BUT GET RID OF DEAD GROWTH

Brown leaves won’t turn green again. Like having a bunch of dead flowers around the place, keeping dead growth on a plant is depressing for everybody. Don’t be afraid to hack it back, maintaining as much of the green plant as possible to encourage replenishment.

JUMP ON WHITE MOULD

Have enough houseplants and you’ll have white mould on some of them – I have a few where it kicks about all year round. In the warmer months, and in small quantities, I consider it fairly harmless. But in winter it can bloom quite dramatically on damp soil. Scrape the white mould off when you see it and, when you water, make sure that the soil is properly dry and drained once you have. Some people also like to dust the surface of the soil with cinnamon powder, which is a natural fungicide. Lends a festive air to the place, too.

TRUST THAT IT WILL GET BETTER

Before you know it everyone will be rushing about, having given up on their new year’s resolutions and saying things like, “I can’t believe it’s February already!”. By March, the days will be longer, houseplants will start to look a little more lively and you can prune and re-pot to your heart’s content. As for the ones who didn’t make it, just consider it a natural spring clean.

GLOOM BUSTERS Group plants near the best light, raising them up if necessary TOUGH TIME Begonia maculata ‘Wightii’, above; and Calathea roseopicta, below