Anne Swithinbank’s Masterclass
QMy houseplants have looked great all summer, but they tend to suffer in winter with poor growth and brown leaf tips. How can I keep them healthy into the colder months this time round?
Penny Fothergill, Cheltenham, Gloucestershire
AWinter can be tough on houseplants and they all react differently to the problems of diminishing light, variable temperatures and dry air. So act now to nip potential problems in the bud and keep plants looking healthy.
Any still standing outdoors after a summer holiday in fresh air had better come in before temperatures plummet. My cymbidium orchids sit out from June to September, experiencing cooler night temperatures to help them set flower buds. Look for slugs hitching a lift under pots. Unlike tropical moth orchids, cymbids prefer temperatures below 60ºF (15ºC).
Other temperate plants like citrus and clivia prefer cooler rooms around 50ºF (10ºC) with less heating. Tropical anthurium (oilcloth and flamingo flower), Amazonian elephant’s ear (Alocasia x amazonica) and zebra plants (Aphelandra) enjoy constant balmy temperatures over 65ºF (18ºC). In our house, we are mean with the heating and have difficulty keeping these alive. Smaller tropicals like snake plants appreciate a terrarium or bottle garden.
Parlour palm, peace lily (Spathiphyllum), satin pothos such as Scindapsus pictus ‘Argyraeus’, maidenhair ferns and the prayer plant tribe (maranta, ctenanthe and calathea) are prone to brown leaf tips or frizzling if the air is parched or their roots dry out. Even this late in the season, it is worth potting on congested plants or those that are in old, stale compost. Keep them away from radiators, and group to create small microclimates of humidity.
For those with few windows, LED bulbs for cultivation will help. Succulents need bright, cool, dry conditions from October to March, because growth made in low light will be long and drawn. Some need an occasional watering to keep from shrivelling; the candle plant (Senecio articulatus) is an exception as it grows actively in winter.
Most cacti survive without winter watering, and pebble plants (Lithops) stay dry from November to June.
I’m giving this Begonia ‘Lucerna’ and maidenhair fern a half-strength general-purpose liquid feed (such as Chempak 3) to perk them up ready for the darker months
Forest lily (Clivia miniata) likes cool rooms and windowsills
Grouping the likes of satin pothos, dracaena, Pilea peperomioides, golden pothos and Scindapus pictus creates a beneficial microclimate