Although potted plants also slow down during the winter, they may need a little extra nutrition to keep them healthy. Some varieties cope with darkness better than others, and if you use grow lights, your houseplants will continue to grow.
Your potted plants need light, water, nutrients and warmth to grow. During the winter – from roughly October to February – growth tends to stop, and so does the need for nutrients. The main reason for this is that the days are shorter.
Flowering or fruiting houseplants such as geraniums, chillies and citrus trees usually have their natural resting period during the winter and should generally not be given any extra nutrients at all. It’s best if they can also be left in a cool place.
However, leafy plants such as house pines and various types of fig trees or Chinese money plants will benefit from a splash of nutrients from time to time, even in winter. The need for nutrients is greater if you use grow lights, have warm indoor conditions or simply have plants that readily grow. During winter, you can reduce the dose (how much) or frequency (how often) you feed your houseplants, so that your plants receive about half of what they normally receive in summer.
Be careful not to overwater your potted plants! Make sure the soil is actually dry before watering.
If you use a grow light and also keep the room temperature up, you can continue to feed your plants throughout the year.
A liquid nutrient is usually most convenient for your potted plants. It is easy to dose according to the instructions on the packaging. Plant food spikes that release nutrients gradually are also available, suitable for green and flowering plants.
It is perfectly possible to use the liquid from, for example, a bokashi compost to nourish your potted plants. As the fermentation liquid has a pungent odour, it is a good idea to dilute it well. For those with sensitive noses, odourless liquid plant food is available to buy.
Various types of plant nutrients may have different nutrient compositions, so there is no harm in using a variety of plant nutrients.
It’s best to replant your potted plants in the spring, just as they’re about to start growing. It’s possible to transplant plants during winter if you really need to (for example, if you get infested with dark-winged fungus gnats), but try to avoid disturbing sensitive varieties.
Remember that the new soil – if you buy new potting soil – is loaded with nutrients from the start. This usually suffices for about 1–2 months.