In September, along with the reduction of daylight hours, I start gradually reducing watering of cacti and preparing them for the winter. While it is still warm outside, I carefully inspect the plants for pests or diseases.
Usually, if the window sill hygiene rules are followed during the summer, a fall inspection will not reveal any problems. But if an unpleasant finding has occurred, now is the time to treat and thoroughly clean the window, window sill and frame to keep the plants safe until the spring.
Why do cacti need dry wintering?
This is what collectors call the dormancy period. It is needed, like any plant, to gain strength and prepare for the next flowering. Many cacti refuse to bloom for years just because of the absence of wintering.
To send a cactus into hibernation, three conditions are necessary:
- lack of watering,
- limitation of light,
- temperature drop.
Almost all species of cacti are not watered from November to March. In their natural environment, they go into hibernation during drought – the lack of rain stops their growth, and cacti go into austerity mode.
In our climate, the dark winter months are the optimal resting period, especially since we cannot change this seasonal feature. If we continue watering with a lack of light, the cacti begin to stretch and lose their shape, new prickles grow weak and unsightly.
It happens that low light and lack of moisture are not enough to start winterizing. If you see cacti stubbornly continuing to grow, measure the temperature on your windowsill: the heat from the radiators can really mess up your plans. The optimum overwintering temperature for most desert guests is around 13-15 °C and unfortunately 22-26 °C, which is tolerable for humans, is not suitable. This is why collectors set aside a separate room for plants.
Controlling the temperature
It is possible to kill two birds with one stone and find a compromise at home. If the temperature on the window sill is not much higher than necessary, you can put on the radiator foil cardboard or similar material – in the room will remain heat, but it will not reach the window sill, because it will be reflected from the radiators to the center of the room.
A more radical way is to attach a greenhouse film to the window opening so that it forms a partition between the window sill and the room up to the height of the window sill. This will reduce the degree of light in the room, but will also serve as an insulating structure. When airing in sunny weather, the cold air will sink to the window sill. Cacti feel good and people stay warm!