Lockdown 1.0 saw many of us throwing ourselves into gardening with renewed passion and appreciation for the calming power of plants. But with the weather looking decidedly less clement for Lockdown 2.0, it’s time to turn our attention to the garden we can care for in the warm, cosy comfort of the great indoors: houseplants. Jane Perrone, freelance writer and host of On the Ledge podcast, shares some guidance and jobs to keep us busy in the weeks ahead:
While we all hope for crisp late autumn days when we can potter about planting bulbs and deadheading the last of the dahlias, much of the gardening jobs that need doing at this time of year fall under the category of heavy, messy work that my father describes as “rolling about under a hedge with a crowbar”.
Don’t get me wrong, I love to don my overalls and steel-toed boots and get stuck in turning the compost heap or digging a planting hole for a new tree. But on the days when the weather is too brutal to venture out, I can retreat to my indoor garden and swap the crowbar and the spade for a hand lens and a spray bottle.
My first job is to make sure that all the cacti and succulents that like to rest all winter are located somewhere cool but bright; if you’ve ever seen an Echeveria that looks like a sketch for a plant in a Dr Seuss book, you’ll know how lack of light can cause succulents to become leggy. The key to avoiding this phenomenon – etiolation, to use the botanical term – is to keep succulents cool and dry. An unheated room with a south-facing window is ideal: check plants every few weeks and only water if they start to show signs of shrivelling.
When moving cacti and succulents to their winter quarters, examine every crevice for signs of mealy bug, who consider these plants a tasty treat. They may look as harmless as a stray wisp of cotton wool, but let them proliferate and their sap-sucking habits will take down the most robust of plants within a few weeks or months. Use a cotton bud dipped in surgical spirit to wipe them away, and check back every few days: like all battles against pests, this is a war of attrition.
Plants from tropical climes will most likely continue to grow during winter, but they may feel the effects of the change in atmosphere brought by switching on the heating; move plants away from radiators, woodburning stoves and other sources of hot, dry air, and compensate by increasing air humidity. Don’t assume that wafting around with a plant mister once every few days will make any difference to the amount of moisture in the air: it’s as effective as brushing dirt from the carpet with a toothbrush. Instead, put a humidifier on your Christmas list, or place a tray of wet pebbles under plant pots. Moving particularly sensitive plants to more humid rooms such as the kitchen and bathroom can help, as can grouping plants together to create a moister microclimate.
So what, you may justifiably wonder, is the point of the spray bottle mentioned above? This I fill with a marvellous mixture called SB Plant Invigorator. This foliar feed-cum-pesticide is pet-friendly and brilliant for keeping on top of the pest that just thrives on leafy houseplants – spider mites. This is where my hand lens comes in, too. Spider mites are so small they are impossible to spot with the naked eye, although you may see grainy white detritus on the backs of affected leaves, which is made up of the mites’ shed skins. Under a botanist’s hand lens (or a jeweller’s loupe or magnifying glass) the red or brown crablike creatures come into focus.
Members of the prayer plant family such as Calathea (recently recategorised as Goeppertia), Maranta and Ctenanthe are particularly popular with spider mites: watch out for specimens that look a little dull and droopy, then deploy your lens for a closer look along the midrib of the leaf underside, for that is where these tiny destroyers like to congregate, emboldened by the hot dry air of the home in winter. There is no silver bullet of a cure for this pest, but daily wiping of the leaves with a damp cloth, ideally after a spray with SB Plant Invigorator, should gradually weaken the mites’ grip on your plant.
Even if your plants aren’t under attack from spider mites or mealy bugs, now is a great time to wipe glossy-leaved plants to remove a buildup of detritus that can block their pores. Hairy leaves and spiny plants prefer to stay dry, so deploy a clean soft paintbrush or makeup brush to remove any dust or stray soil.
Deploy the watering can with discretion during this time: although there are a few houseplants that love to sit in water, such as umbrella grass (Cyperus alternifolius), most prefer a more judicious supply of moisture. Don’t just water once a week because that’s what you always do (or, increasingly these days, because your plant app is telling you to): instead, test the soil first. You can invest in a moisture meter, but a wooden kebab stick thrust in among the roots and left for a few minutes will tell you everything you need to know once withdrawn. If the stick comes out dry, it’s time to water: if damp, hold off a little longer. If you are lucky enough to have a source of rainwater, do use it on your houseplants, as some species are sensitive to the mineral salts present in ‘hard’ water areas, while others still suffer when irrigated with water containing fluoride. That said, many plants will get by just fine on tap water, especially if you occasionally take the pot to the bath or sink and flush out the potting compost for a minute or so with water to remove any buildups. Whether from the tap or the rainwater butt, make sure you use water that has been brought to room temperature first, to avoid shocking your plants.
Whether you have one houseplant or a hundred, your main impulse this winter should be to simply observe and enjoy your plants. Placing particularly beautiful plants in your eyeline – whether that’s on your office desk or on the windowsill by the kettle or the sink – allows you to revel in the beauty of an orchid flower or the marvel at the way the light hits a variegated leaf. The more you look, the more you will spot the subtle changes that are your plant’s way of communicating its needs: whether that’s a drooping leaf or a flush of new growth.
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