Since petunias are usually available relatively cheaply in gardening stores, the frost-sensitive plants are usually only cultivated as an annual and bought new every year. If you don't want the effort of overwintering, you can also grow the young plants yourself for the new season.
How can I grow petunias myself?
To grow petunias yourself, you can either harvest seeds and grow them on the windowsill from February or March or cut cuttings from strong mother plants in spring and root them in potting soil. Make sure there is consistent humidity, temperatures around 20 degrees Celsius and no direct sunlight.
Harvest the petunia seeds yourself
If petunias are not grown in a covered balcony location, they are even more likely than usual to have unattractive and disease-promoting clumping of the withered flowers. That's why it's common practice to regularly pluck off wilted individual flowers during the long flowering period of petunias. However, you should at least partially refrain from doing this if you want to harvest ripe and germinable seeds from the petunias yourself. In this case, just carefully remove the petals and wait until the green pistil has turned into a brown, mature and round seed capsule.
Grow your own petunias from seeds
Since petunias are extremely sensitive to freezing temperatures, the young plants from seeds should be grown on the windowsill for a strong start to the gardening season. To do this, sow the small seeds from February or March in pots, bowls or, ideally, in an indoor greenhouse (€24.00 on Amazon). You should create the following conditions:
- an evenly moist climate (easy to control with a cover or foil)
- Temperatures around 20 degrees Celsius
- a permeable, fine-crumbly growing substrate
- no direct sunlight
The plants can be pricked out and separated as soon as the second pair of leaves have finished developing. However, when planting in the garden or on the balcony, you should first gradually harden the sensitive plants with regard to temperature and direct sunlight.
Propagate petunias through cuttings
To grow offshoots from cuttings, you first need a few strong mother plants in spring. Cut off sections about 15 centimeters long from which you remove the leaves at the bottom. The cuttings root relatively easily in a glass of water or directly in loose potting soil. Whether the rooting was successful can be seen by the emergence of new leaves at the tips of the shoots.
Tip
Growing petunias from seeds is not possible without restrictions for all varieties. For example, with hybrid hanging petunias from commercial stores, the typical characteristics are not passed on intact. There are also self-sterile varieties that do not produce any germinable seeds.