Annual sunflowers (Helianthus annuus) are not hardy and cannot tolerate subzero temperatures at all. They have to be re-sown and planted every year. When is the best planting time to plant the popular summer flowers?
When is the best time to plant sunflowers?
For a successful sunflower planting, you should plant the seeds indoors in pots from the beginning of March. Plant early sunflowers outdoors or in containers at the end of May. Alternatively, you can sow seeds directly outdoors at the end of April.
First sow, then plant
Sunflowers are sown first. You can sow seeds in small pots or a seed tray indoors. You can also sow the seeds directly outdoors.
The disadvantage of sowing outdoors is that it is not warm enough outside to germinate the seeds until the end of April.
It is therefore advisable to grow sunflowers indoors and plant them in the garden or in pots on the balcony at the end of May.
Prefer sunflowers in the house
Sowing indoors is possible from the beginning of March.
- Prepare pots or seed tray
- Place cores in the ground
- Keep soil moist
- Set up warm and bright
Put three to five seeds into each seed hole, as not all seeds usually sprout. The seeds germinate relatively quickly. Once the plantlets have developed two or more leaves, remove any weak sunflowers and leave only the strongest ones. Repot the sunflowers if necessary.
It has proven useful to plant sunflower seeds as sprouted sprouts. Otherwise, more of the seeds will be stolen by birds.
Sowing outdoors from the end of April
If you want to sow the sunflowers directly outdoors, you should wait until the end of April. Prepare the soil and sow three to five seeds each, approximately two centimeters deep.
Plant early sunflowers at the end of May
You should not plant pre-grown or pre-germinated sunflowers outdoors before the end of May. Even a short burst of frost causes the delicate plants to freeze.
Sunflowers that you would like to cultivate in a pot can also be planted earlier. But bring the containers back into the house when the weather forecast calls for night frost.
Tips & Tricks
Perennial sunflowers, in contrast to annual varieties, are largely hardy. The best time to plant the perennials is August. Sunflowers planted in late summer will bloom the next year.
