The nasturtium is not hardy and cannot tolerate frost at all. Even with the first night frosts, the above-ground parts of the plant freeze. If you want to overwinter your nasturtium, you should take action beforehand.
How does nasturtium survive frost?
Nasturtium is not frost hardy and does not tolerate frost. To overwinter it should be transplanted into a large pot and kept in a bright, frost-free place. Be careful to water less in winter, but do not let the soil dry out.
However, you should first make sure that your nasturtium is actually a perennial variety. There are now numerous new breeds with many color variations. Unfortunately, most of them are annuals.
Overwintering nasturtiums properly
Cut back your nasturtium from the flower bed in autumn and plant the tuber in a large pot. Place this in a bright and frost-free place, for example in the winter garden. How far you cut back the nasturtium depends, among other things, on the space available.
If you already have your nasturtiums in pots or boxes on the balcony or terrace, there is no need to transplant them. Just cut off wilted flowers and leaves and put the plants in their winter place. You can limit watering a little during the winter months. However, be careful not to let the soil become too dry.
The most important things in brief:
- not frost hardy
- annual and perennial varieties
- winter brightly and frost-free
Alternative for wintering
If you don't have room to overwinter your nasturtiums but would like to plant the same varieties next year, then there is an alternative for that too. Take cuttings from your old plant or take seeds to sow in spring.
The cuttings initially require less space and a smaller pot, but are genetically identical to the original plant. In spring they can be planted out directly after the Ice Saints and you won't have to wait too long for the usual blooms.
If you have decided to collect the seeds, you should dry them carefully so that they do not become moldy. You can start sowing on the windowsill or in the heated greenhouse as early as March.
Tips & Tricks
Before overwintering, check your seed packet to see whether you bought an annual or perennial variety.
