Poinsettia (Euphorbia pulcherrima) with defocused Christmas tree in background

Your winter house plant jobs

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The growing conditions in our homes change as winter approaches. As the days get shorter there’s less light, temperatures inside can fluctuate as we turn on the central heating and the air becomes drier. The needs of plants change too, with some plants becoming dormant therefore needing less water and no plant feed, while those that are in flower will continue to need more attention. So the key to keeping house plants happy at this time of year is to make a few simple changes to their growing routine.

More house plant advice:

Winter house plant needs

Light

Dusting houseplant leaves — Dusting house plant leaves helps them to absorb more light

As the shortest day approaches, maximising light levels at this time of year is important. This can be as simple as moving a plant closer to a window or into a brighter room. My dragon tree (Dracaena marginata), for instance, is normally about two metres away from a window in a bright south-facing room. It’s happy there from late spring to mid-autumn, but during its first winter I noticed it was starting to lean towards the light, so I now move it in autumn to in front of the south-facing French doors. It would develop leaf scorch here in summer but there’s no danger of that at this time of year. But not all plants will need to be moved, for instance, shade-loving house plants such as aspidistra should take winter light levels in their stride.

Keeping windows clean can make a big difference to the amount of available light, as can wiping the leaves and stems of house plants to remove dust that collects on them – as dust builds up it inhibits the plant’s ability to absorb daylight. A damp cloth is ideal for this task, but for leaves that are hairy, spiky or furry use a dry artist’s paintbrush instead. It’s also a good idea to rotate plants every week so that the whole plant is exposed to an even amount of light – this will prevent plants from becoming lopsided. If your home is particularly dark in winter, or you have plants that are struggling, there’s also the option of providing additional artificial lighting using full spectrum LED grow lights.

Heating

House plants generally prefer even, steady temperatures but it can be tricky to provide this during winter with cold draughts in hallways and single glazing causing cold spots, and radiators and fires creating hot spots. Again, a bit of house plant relocation might be necessary, for instance, moving plants that sit on shelves above radiators, or that spend the summer on a table by the front door.

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During winter, the temperature can also fluctuate more between night and day, particularly on windowsills where curtains or blinds are closed in front of the sill trapping cold air behind them. Leaving curtains open will help, but as we’re all trying to save money on our energy bills, letting heat escape this way isn’t great for the bank balance, so when temperatures are forecast to dip below freezing, move plants off windowsills at night.

Humidity

Heating a home tends to dry the air, which is fine for succulents which come from hot, arid places but not ideal for house plants from tropical and sub-tropical regions which prefer some humidity. The difficulty is balancing their need for a humid atmosphere without creating a damp environment where mould starts to grow, which can be a health hazard for humans.

Misting is often recommended but the effects don’t tend to last long enough to create sufficient humidity, and water droplets sitting on leaves can cause fungal problems at this time of year. One of the simplest ways to boost humidity levels is to gather plants together in groups so that they create their own microclimate as the plants release moisture through their leaves via transpiration. Humidity-loving plants can be grouped together in rooms where moisture levels are higher such as the kitchen or bathroom.

I move some plants into my utility room where I dry clothes in the winter and the plants seem to like the extra moisture that’s released as the clothes dry. Another option is to use a pebble tray. Fill a water-tight tray with a layer of gravel or pebbles at least 2.5cm (1in) deep, then top this up halfway with water. Place the plant pots on top of the pebbles, if the pots have holes in the base make sure they aren’t standing directly in the water as this can cause the roots to rot. As the water evaporates this will humidify the environment around the plants. Keep an eye on the water level and top up as necessary.

Water

Over-watering is a much more likely cause of death for a house plant over winter than at other times of the year because a plant isn’t actively growing and therefore doesn’t need as much water as normal. Watering every week at this time of year will cause the compost to become saturated and the plant’s roots to die, so it’s always better to err on the side of under-watering in winter.

Having said that, plants in warm rooms will dry out more quickly and plants that are flowering at this time of year will still need regular water, so it very much depends on the plant – succulents might need to be watered once a month, foliage house plants every fortnight or so depending on how dry the compost is and flowering plants once every seven to 10 days. A moisture meter which is inserted into the compost is a handy tool for indicating whether you need to water or not, but I just use my finger, pushing it into the compost to the second knuckle. If your finger comes out dry then water, if the compost feels moist wait a few days then check again.

Water from the cold tap at this time of year is likely to give plants a cold shock, so it’s much better to apply tepid water or fill your watering can then allow the water to come up to room temperature before using.

Food

As plants aren’t growing at this time of year there’s no need to feed them. Applying nutrients that aren’t used by the plants can cause minerals to build up in the compost which can damage the roots. You can resume applying a fertiliser in March as plants start to grow again.

Pest and disease problems

Aphids can be brought indoors on new plants or they can fly in through open windows or doors

Just because it’s winter doesn’t mean that you can let your guard down when it comes to pests. They can hitch a lift on house plants that have spent the summer outdoors, be stowaways on house plants that you’ve just bought or they can fly in through an open door or window, taking the opportunity to take up residence indoors as the weather turns cold. Aphids, whitefly, spider mites, mealy bugs and scale insects are the usual suspects.

I now isolate any new house plants for a couple of weeks, after I once bought some succulents that turned out to have mealy bugs which in turn spread to more established plants. Carry out a pest patrol once a week, looking under leaves, around leaf axils and checking the stems too. This will mean you can spot a problem quickly and nip it in the bud. The easiest and safest way to remove pests is by hand, wiping them off with a damp cotton bud. I also use a plant invigorator spray which works as both a non-toxic pesticide and foliar feed which is sprayed on to the leaves.

Low light levels and poor air circulation can lead to the fungal disease botrytis, a grey mould that causes rot. Good plant hygiene will help to prevent this – remove any yellowing or dead foliage as soon as possible, clear away any debris from the surface of the compost and avoid wetting foliage by watering from below – place a plant pot in a bowl filled with a couple of cm of water and leave it there for about 10-15 minutes until the surface of the compost feels moist.

Thrifty tip

Hang on to old toothbrushes because they can be used to remove scale insects. This pest has a hard outer shell-like structure and can be found in clusters clinging to stems and the undersides of leaves. They are more difficult to remove than pests such as aphids, but I’ve found a toothbrush moistened with soapy water can be used to carefully scrub away the scales.

Seasonal Stars

Cyclamen

Cyclamen persicum, also known as the florist’s cyclamen, is tender and won’t survive the winter outside. It does, however, make a colourful house plant with blooms in festive red, vibrant magenta or frosty white and handsome heart-shaped, bottle green leaves that are marbled with silvery-grey.
It can be tricky finding the right home for it – too warm and too bright and it will think it’s spring and become dormant; a north or east-facing spot is ideal. Over-watering and fungal disease are potential problems. To avoid these I wait until the leaves droop a little before watering from below. Snip off any faded flowers.

How to grow and care for indoor cyclamen

Poinsettia

Poinsettia, Euphorbia pulcherrima, has become synonymous with the festive period thanks to its colourful red bracts set amongst dark green foliage. It’s native to Mexico so it doesn’t like a chill, in fact the journey from the supermarket or garden centre to your home is when it’s most vulnerable. If a new plant sheds leaves it’s likely it has experienced a cold shock. To prevent this I like to take some sheets of bubble wrap with me when I plan to buy a poinsettia so that I can wrap it up for the journey from the shop to home. At home they need a minimum temperature of around 15°C in bright but indirect light. Only water when the compost feels dry and increase the humidity by placing it on a pebble tray.

How to care for poinsettias

Moth orchids

Pink flowers of moth orchid — Keep feeding orchids to keep them flowering

Phalaenopsis orchids, or moth orchids, can bloom at any time of the year and several of mine flower reliably each winter. They’re also really easy to look after, thriving in our centrally heated homes. Getting the watering right is key – the roots need to be moist but not waterlogged. Orchid compost is made from bark which doesn’t have the same ability to suck up water as typical house plant compost, meaning watering from below not an option.

The easiest way I’ve found to water them is to set the mixer tap so that the water runs tepid then I hold the pot under the tap for 20-30 seconds. Do this every 2-3 weeks during winter. They like a bit of humidity so position them in a light-filled kitchen or bathroom or stand on a pebble tray. Feed every 4-6 weeks during winter – use a specialist orchid feed that will encourage more flowers.

Snake plant

Sansevieria, whose common name is mother-in-law’s tongue or snake plant, is one of the easiest house plants I grow, adapting well to the lower light levels and temperature fluctuations of winter and needing no additional humidity. I have several on north-facing windowsills that are above radiators and they all make it through winter without any problems. It doesn’t need much water, so in winter I wait until the compost has dried out before watering.

How to care for a snake plant

Echeveria

Echeveria are one of my favourite succulents, with rosettes of pointy, fleshy leaves in a range of colours from green or purple-grey to glaucous blue. They’re from Mexico and South America and don’t like the combination of cold and wet a British winter brings so I move mine indoors onto a bright, sunny windowsill before the first frost. I also like to use them on the table for the Christmas Day feast, popping them in sparkling pots and gathering them in a cluster with fairy lights weaving among them.

They need little in the way of water over winter, so I water sparingly every four to six weeks. As my succulents grow in tight-fitting pots I do this by using a small indoor watering can with a narrow spout so that I can direct the water around the sides. It’s not unusual in winter for the outer leaves to start to wither and die back – this is perfectly normal. These can be removed in spring when you repot.

Growing Greener

Rather than treating cyclamen as disposable plants after they’ve finished blooming give them a bit of TLC and you can keep them for the following winter. Once the flowers have faded stop watering to encourage the plant to become dormant. Put the pot in a cool, shady spot and place the pot on its side so that the compost stays on the dry side – water sparingly very occasionally. In early autumn repot and start to water again.