Petunias originally come from South America and are usually only cultivated as annual balcony plants in this country. In some cases it is quite possible to get the flower-rich petunias through the winter with sufficient care and in a protected place.
Are petunias hardy and how do you overwinter them?
Petunias are not hardy and very sensitive to frost. In order to get them through the winter, they can overwinter in a bright room at 5-10 degrees Celsius, although regular care and checking for pest infestation is required. Shoots should be shortened to 15-20 cm.
Be careful with petunias
While some potted plants can withstand temperatures below zero for a short time, petunias and their various subspecies are all very sensitive to frost. Therefore, make sure to protect the plants from any kind of hypothermia, as this usually leads to the death of the entire plant. If you buy new petunias every year as young plants for the balcony, you can simply let the petunias bloom until the first frost and then compost them. To attempt overwintering, the plants must be brought into their winter quarters before the first frost and only wintered out again after the Ice Saints.
Overwinter the petunia under suitable conditions
Surphinias, which are valued as petunia cultivars because of their better weather resistance, are also extremely sensitive to frost. However, since Surfinia are available in particularly attractive color combinations and cannot be grown from seeds due to their pronounced self-sterility, it is also worth overwintering them in a protected room. The following conditions should prevail in this:
- as bright as possible (however, no direct sunlight is necessary on the plants)
- Temperatures between 5 and 10 degrees Celsius
- regular care
The comparatively low temperatures for overwintering petunias can best be achieved in a tool shed or basement. However, the plants should be easily accessible as they must not dry out and should be checked regularly for pest infestation.
Preventing difficulties during wintering
When putting them into winter quarters, balcony boxes with petunias should be checked for possible aphid infestations so that they cannot spread massively over the winter. The right plant substrate ensures that moderate watering prevents the plants from drying out and prevents waterlogging and root rot from occurring. The shoots of the petunias are shortened to 15 to 20 centimeters long for overwintering. Flower buds are removed in winter so that the plants are not energetically depleted in their winter quarters.
Tip
If you don't have the right space to overwinter the non-hardy petunias, you can also collect the seeds in autumn and grow young plants from them on the windowsill from February onwards.
