If you don’t want to give your petunias to the compost in autumn, you can also overwinter them. Important are the appropriate winter quarters and the right care. With these tips the overwintering of petunias is successful.
Bright flowers full, delicate fragrance and in the window box the perfect planting partner for other sun-hungry little flowers on the balcony: Petunias (Petunia) are among the most popular balcony flowers and grow with weekly liquid top dressing to true flower waterfalls or flower seas. Only with iron deficiency, the leaves of a petunia turn light yellow, while the veins remain green. Therefore, the care of a petunia includes a weekly portion of liquid fertilizer, preferably petunia fertilizer with a decent amount of iron.
Whether for the garden or the balcony, petunias are available inexpensively in stores in the spring, so wintering is hardly worth it. Unless you can’t bring yourself to throw the flowers away before winter, have a rare petunia variety or a specimen that is particularly dear to you.
How to overwinter petunias?
No petunia tolerates frost. Wintering is done either as a plant or as seeds, which you sow the next spring. Sowing petunias yourself is not difficult and usually works without problems. However, seeded young plants do not always match their parents in appearance. Dry the seeds collected in early fall and store them in a cool, dry place, preferably in a coffee filter and cool basement, until spring. In early March, sow the seeds in sowing soil and place the container in a warm, bright place at 20 °C / 68 °F. This is also a great way to propagate the plants.
Overwintering petunias as a plant
Petunias appreciate plenty of light and cool temperatures even in winter. If you want to overwinter a petunia, stop weekly fertilizing from the beginning of September. Overwinter the plants in their window boxes or containers. Before the first frost, cut the shoots of the plants back to a good 15 centimeters (6 in) – especially the shoots that are not yet woody. Remove blossoms as well as dried up parts. At the same time, check the petunias for obvious pest infestation on the shoots and for diseased leaves. Otherwise, pests and plant diseases can make life difficult for petunias in the winter quarters and lead to total failure.
What does a winter quarters for petunias?
Winter quarters should be frost-free, and the location especially bright. The ideal place is a room temperature between 5 and 10 °C / 41 and 50 °F. To prevent petunias from sprouting in winter, the temperature should not fluctuate and the flowers should not be exposed to drafts or heating. Even short-term increased temperatures can stimulate the shoots to sprout. This can not be avoided anyway, but you do not have to encourage it.
Proper care for petunias in winter
Water very little. This is one of the most important tips, because petunias rot very quickly in wet, cold soil; the main reason why the flowers die in the cold season. The substrate may calmly dry out a few centimeters deep, until the plants want a new sip of water.
Pests usually drag themselves to the winter quarters as eggs, which adhere to the shoots and hatch in the winter. You can give the plants a strong shower in the fall as a preventive measure, but then you must not give them any more water for the time being. In winter, so-called water sprouts will form. These are fresh, light green shoots that sprout under a lack of light and are extremely elongated and small-leaved. You should cut these off. They have no value for the flowers, break off easily and are at most food for pests.
Petunias overwinter: More tips on care
Wake the plants from their hibernation starting in February, place them warmer and water them a little more. When they sprout, pot the petunias in fresh soil and then place them in a bright and warm spot, for example on a windowsill. Depending on the weather, the plants may well go outdoors as early as April. In the sun, however, not yet, for this the plants must first harden off a few days in the shade. If the nights are still cool or there is still a threat of frost, the flowers must be brought back indoors. Finally, petunias can be put in the garden and on the balcony only in mid-May.