Preparing Your Indoor Plants for Winter

by Sarah Gardiner

Sarah is a horticulturist with a passion for edibles and cottage gardens.

While days here in the southern hemisphere are getting shorter, we’re all starting to feel the chill of winter fast approaching - with more frequent crisp mornings and gloomy, dark evenings. It’s no surprise that this cool change in the air makes us want to crawl into bed and stay there until the warmer weather returns. It wouldn’t be crazy to think your houseplants are feeling the same. Majority of our plants have put in a good effort after their growing season and now that the temperatures are dropping, it’s time for them to slow down.

Throughout winter, our house plants are more susceptible to common problems with the changes in light, temperature and humidity. Many of the plants we grow indoors are tropical, heat loving plants that might start to suffer with the change of seasons. We’ve compiled a list of tips, tricks and signs to look out for, to ensure your plants have the best chance of cruising through a long winter to see the bright light at the end of the tunnel with spring’s return.

Bright light can be harder to find throughout the winter months when the sun appears to be lower in the sky. Rooms that were once filled with warm, natural light might suddenly feel gloomy and cold. If you notice this, it’s important to remember that your plants might need to be repositioned into a brighter spot. Check sunlight requirements for all of your plants and move them accordingly into positions that are warmer and more brightly lit.

One of the most important things we can stress when it comes to winter plant care is to slow down on watering during this time. As your plants aren’t growing as actively, they require less water and are much more at risk of being overwatered. With much cooler temperatures, the soil in our pots retains more moisture, staying wet for longer periods. Remember not to water your plants while their soil is wet and leave longer intervals between watering than you would in the warmer months. An easy way of figuring out if your plant needs watering is to push a finger about 5cm into the soil and if it comes out clean, it’s safe to say your plant is ready to be watered. If in doubt, a handy Moisture Meter is a cheap and easy tool to help.It’s also a good idea to water your plants in the morning rather than the evening, to ensure they have most of the day to drain away any excess water from their pots. Cold tap water can shock your plant roots during the cooler months and plants will respond better to being watered with tepid water.

Watch the temperatures inside your home by avoiding extremes. Although most of our tropical or subtropical indoor plants might like warmer temperatures - they still don’t want to be in the artificial hotbox that is your lounge room with the gas heater blasting. Equally, keep them out of cold draughts you might encounter in doorways or windowsills. Most houseplants thrive in temperatures of 15-24°C, so for best results, try and keep within this range. Frequent temperature fluctuations can cause stress to your plants and potentially kill them, so try and keep it as consistent as possible.

Warm, sunlit rooms are the ideal position for your plants throughout the cooler months.

Throughout winter, humidity drops rapidly and is often made worse by the effects of heaters and air conditioning units, which tend to dry the air out even more. For many of our tropical indoor plants; like ferns, Begonias, prayer plants and many Aroids, this can be a big problem. With lacking humidity and dry air, it is common to see your plant leaves looking dull, dry and crispy. A good way of counteracting this is by huddling your plants together, to increase humidity and maintain higher temperatures. Placing your plants on a saucer of pebbles with a small amount of water, in a brightly-lit spot is also a good trick to increase humidity around your plant.

We’ve told you before to slow down on the fertiliser coming into the winter months... and we’re telling you again. Plants are not in their active growing period at this time and don’t require the extra nutrients. Another reason not to fertilise is that lower soil temperatures mean soil microbe activity is reduced, meaning fertiliser at this time goes unutilised. Hold off on fertilising until the start of spring when your plants start to put on new growth again.

Lower humidity and dry air means some of your houseplants are more susceptible to pests like spider mites and mealybug. Keep an eye out for these and use preventative measures like wiping smooth leaves down with a damp cloth and leaf conditioner, to avoid pests attacking where dust builds up on their leaves. Not only will this keep your plants looking clean and glossy, but will increase their ability to photosynthesise.