In the wild, geraniums grow in areas with dry, cool and light winters – a far cry from our harsh winter climate. Geraniums are consequently frost-sensitive and need to be moved indoors in winter. Although most geraniums will survive the winter at cooler room temperatures in your brightest window, it’s a little too warm and a little too dark to be optimal. If you want to give your geraniums the very best conditions, read our top tips.
As soon as the first frosts threaten, it’s time to bring your geraniums in for their winter rest. Usually you can tell when the time comes: growth stops, flowers become fewer and leaves may start to change colour.
You can remove decayed flowers and leaves from the geraniums, but you do not need to repot them. It is better to repot your geraniums in early spring, when growth will start again. However, some people prefer to repot in new soil, or at least replace the top layer of soil, in the autumn if the pot has been outside all summer long.
Bright and frost-free is the most common recommendation for overwintering geraniums. This means 5–10°C and with 8–12 hours of daylight.
The warmer the temperature, the more light the geranium needs. The cooler the temperature, the less light the geranium needs. This is the same for all potted plants. If you are going to overwinter your geraniums in the dark, the temperature should therefore be kept slightly cooler (but frost-free). It is also wise to cut the plant back a little.
You can stop feeding in the autumn to give the geranium a chance to rest. Once the geranium has gone into dormancy, water very sparingly. Read more about potted plants in winter here.
If your plants are flowering at room temperature and with grow lights, you can give them some plant food. The same applies if you grow geraniums hydroponically during the winter.
If you have your geranium next to the window, you’ll see when it comes to life! In March, light begins to return to most of the country and your dormant plants start to grow. If you have them in a cool room, now is the time to get them out. Take the opportunity to prune tired branches and possibly repot in some new soil.