Your spring house plant jobs

Indoors, the extra light and warmth on windowsills means house plants will start to regrow after their winter dormancy, so now is the time to give your plants the botanical equivalent of a spring clean, including dividing and repotting them if necessary. There’s something very satisfying about spending a couple of hours one day in early spring gathering in all the house plants from the various shelves and sills where they’ve spent the winter months, then spreading out some newspaper on a work surface and lining up all the equipment I’ll need for a spot of house plant TLC.

More house plant advice:

• 7 ways to save money on house plants
• Unusual house plants to grow
• Growing and caring for house plants with Monty

Spring house plant needs

Light

To make the most of any spring sunshine, I like to give my windows a clean on the inside and out to remove any dirt that has built up over winter. I also carefully wipe the leaves of house plants with a damp cloth to remove dust that has collected on the foliage as this can inhibit a plant’s ability to absorb light and photosynthesise. For plants with spiny leaves, such as cacti, which are awkward to clean, or hairy leaves, which would be damaged by moisture, use an artist’s brush or a makeup brush you no longer use – just make sure it’s clean – to sweep away any dust.

Be careful with plants that have been moved closer to windows over winter to maximise light levels. As the sun gets stronger through mid to late spring it might be necessary to move these plants away from the glass as the sunlight intensified by the glass can cause brown, dry patches on leaves known as leaf scorch. East or west-facing windows suit many house plants better than south-facing situations, as the plants get plenty of bright light either on a morning or in the late afternoon, rather than when the sun is at its strongest at midday. Windowsills in front of frosted windows are great locations for house plants because the frosting diffuses the light reducing its intensity.

Heat

Early to mid-spring can still be cold - and even if the days are warm and sunny, clear skies at night can lead to hard frosts. It’s good to be aware that the temperature on windowsills can fluctuate significantly at this time of year, so it’s important to try to maintain an even temperature indoors using your thermostat, and be prepared to move plants off windowsills at night if cold weather is forecast.

As spring progresses and the temperature rises, we can turn off the central heating. This is when plants that I had to move in winter so that they weren’t next to the woodburner or radiators can be moved back to their original locations.

Humidity

In spring, I like to give moisture-loving tropical plants a humidity boost by moving them into the bathroom while I have a bath or shower. I’ll leave them there for a few hours afterwards to absorb the extra moisture in the air. If you have plants standing on pebble trays to increase the humidity around them, make sure you keep the water levels topped up in the trays as they will drop when the water evaporates.

• How to raise humidity for house plants

Water

After watering house plants sparingly, if at all, over winter, it’s now time to start watering more frequently so that there is plenty of moisture for the roots to fuel the growth the plants will make over the coming months. It’s important not to overdo it though. Check the soil once or twice a week using a moisture meter pushed into the soil, or use your finger – push it down about 2in (5cm) and if the soil is dry give the plant a water.

For orchids it’s slightly different. Your orchid is likely to be growing in a clear pot and this helps you check whether the roots need watering or not – if they’re a grey colour they do, if they’re green they don’t. I hold the orchid’s pot under a running tap for about 30 seconds to flush the compost, turning the pot so that all of the compost is thoroughly soaked, but you can water just as easily with a watering can. I have a mixer tap and I set this to tepid so that the plant doesn’t suffer from cold shock, but you can just add a bit of hot water to cold in a watering can or fill the can and put it to one side for an hour or so to allow it to come up to room temperature.

• How to water house plants

Food

As plants start to show signs of new growth, it’s time to start feeding them again. Once a month is a good rule of thumb, but some plants may need feeding more or less frequently, so it’s always worth checking a plant’s individual requirements. Use a liquid house plant feed for foliage plants, specialist feeds for orchids and cacti/succulents, and a feed that’s high in potash for flowering plants such as Streptocarpus. Dilute the feed in a watering can and apply to the compost – for the specialist feeds follow the instructions on the bottle, for a high potash fertiliser such as tomato feed dilute to half the recommended dose.

• How to feed house plants

Pest and disease problems

Soft, new growth in spring is a beacon for sap-sucking pests such as aphids, so keep an eye out for any signs of pests so that they don’t turn into an infestation. I tend to set aside a bit of time on a Sunday morning to tend to my house plants, and I’ll use the opportunity to look for pests, checking in particular the undersides of leaves and around leaf axils, which are the perfect hiding spots for creatures. If I do come across any, my first course of action is to remove them by hand – a damp cotton bud can help for those that are tricky to get to.

Spider mites are tiny creatures that are hard to see without a magnifying glass. They thrive in dry conditions, so centrally-heated homes are the perfect place for them to overwinter. In spring, the eggs hatch and an infestation, often indicated by a fine webbing on leaves and shoot tips, can build-up quickly. Misting the foliage every couple of days and using an invigorator spray to maintain healthy plants can prevent spider mites taking up residence.

Maintenance

Remove any growth that has withered or turned yellow using clean, sharp secateurs. Cut back to a growing point, which is generally marked by a bump on the stem – this is a leaf node where new leaves or stems will emerge. If a whole stem needs removing cut back to just above the compost level.

When moth orchids (Phalaenopsis) have finished flowering, cut back the stem to just above the node below the lowest flower. This will hopefully encourage another flush of flowers, but it doesn’t always work and sometimes the stem turns brown. If this is the case simply cut the whole stem back to the base.

It’s always a good idea when handling house plants to wear gloves as they can contain toxic substances.

Repotting

Repotting gives a plant more room to grow and is an opportunity to refresh the compost, and early to mid-spring is the best time to tackle this job, just as plants are starting to regrow.

Generally, house plants are slow growers and may only need repotting every two to three years – the sign that they need to be moved to a bigger pot is lots of roots poking out of the bottom of the pot. Choose a pot that’s the next size up from the previous pot, so just an inch or two bigger in diameter. Make sure the pot has drainage holes and, if it has been lying around in the shed, give it a quick wash in hot, soapy water to get rid of any possible pests or diseases that it might be harbouring. Fill the base of the pot with a peat-free house plant compost, a specialist compost for cacti and succulents or bark compost for orchids, then position the plant and fill in around the sides with the compost. Water well and allow the pot to drain fully before placing it back in its cache pot. Repotted plants shouldn’t be fed for four to six weeks to allow the roots to establish.

I repot my Sansevieria plants every spring because I don’t want them to grow so big they can no longer fit on my windowsills. Rather than moving these into bigger pots I take this opportunity to divide the Sansevieria, carefully pulling away the side shoots that have developed. I either repot these into individual pots or compost them if I don’t need them. I’ll then repot the parent plant in its original pot.

If I have the time I will refresh the compost of plants that don’t need to be moved into a bigger pot. I’ll tip the plant out of its pot, removing any compost from the base of the pot, then I’ll carefully tease away some of the compost from the roots. Using fresh compost, I’ll refill the old pot with fresh compost, replace the plant and fill in around the sides. This is a great way of giving plants a boost in spring.

Growing Greener

When you’re repotting house plants it’s just as important to use peat-free compost as it is for garden plants, if we’re to play our part in saving peat bogs from destruction to preserve their biodiversity and their ability to store carbon. Seek out suppliers of house plants that have been grown in peat-free too. 

Seasonal Stars

African violet

Streptocarpus ionanthus, more commonly known as the African violet, forms a rosette of green leaves, which are sometimes reddish-purple on the undersides, and a profusion of flowers in purple, shades of pink, red or white on and off throughout the year. Recent plant breeding means there are lots of new colours and flower forms available including doubles, ruffled petals and bell-shaped blooms.

It’s native to tropical east Africa and likes plenty of diffused light, warmth and some humidity, although because the leaves are hairy it’s important they don’t get wet so, rather than misting, place the pot on top of a pebble tray or keep it in humid room such as a bathroom or kitchen.

Natal lily

Clivia miniata AGM, or the natal lily, is from South Africa and features strap-shaped, dark green leaves and sturdy stems crowned with clusters of trumpet-shaped blooms in red, orange, yellow or cream in spring and summer. Provide filtered light – direct sun in summer can scorch the foliage – and a cold spell of around 10C is needed from November to February to encourage flowers to form.

Cape primrose

Streptocarpus, or the Cape primrose, is another fantastic plant from Africa. I love it because it’s hard to beat for indoor flower power, and the cultivars come in such a wide range of colours, some with distinct veining and others with frilly-edged petals. If you fancy something with daintier blooms then I’d recommend the lilac-coloured S. saxorum which makes a lovely trailing plant.

They need plenty of light but don’t like hot sun, so an east or west-facing windowsill is ideal. I find it easiest to water from below, as it means I avoid splashing the leaves. Feed every fortnight with a potash feed that’s diluted to half strength.

Jade plant

Crassula ovata is more widely known as the jade plant or the money plant and is one of the easiest house plants I grow. I love that as the plant matures it develops a mini tree-like structure with a thickening stem that resembles a trunk. The oval-shaped, green leaves are fleshy with a glossy sheen and a red tinge to the leaf tips.

Native to South Africa and Mozambique, it likes plenty of light and can take some direct sun. It’s happy with normal humidity levels so doesn’t require misting or a pebble tray. Water the pot fully, then let the compost dry out before watering again. If a plant gets too big for its space, I take a stem cutting by removing a side stem about 8-10cm (3-4in) in length. I’ll remove some of the lower leaves then I push the stem into a pot filled with a succulent compost and added grit or perlite. Water the compost sparingly and roots should develop in a couple of weeks.

Thrifty tip

If you don’t know whether a plant will survive in your home or with the amount of care you can give it, medium-sized or large house plants can end up being an expensive mistake. I know how disheartening it can be to have to get rid of a plant that demanded more attention than I could give it or that needed more humidity than I could provide.

Fortunately many garden centres sell baby plants for terrariums for a couple of pounds each, and these are an inexpensive way to see whether a plant is suitable. If the plant isn’t happy the loss of a couple of pounds is much easier to take than £20 or more. You also get the pleasure of nurturing a baby plant to maturity rather than buying the instant version.