Sunflower sowing: when is the best time?

With their large, bright yellow flowers, sunflowers are an absolute eye-catcher in any garden. So it's no wonder that they are increasingly being found in more and more gardens. The annual plants have to be sown from new ones every year. The question of when to sow the sunflowers naturally arises. The answer to this depends - as is so often the case with the garden - on the weather and temperatures.

Helianthus annuus

The botanical name of the sunflower makes it clear: it only blooms for one year. That means: Sunflowers develop within one vegetation period from the seed to the finished, blooming and fruit-bearing plant. Their lifespan usually ends in late autumn. It does not tolerate frost and is generally very sensitive to freezing temperatures.

Normally, a sunflower is disposed of at the end of the growing season, as it would not survive the winter anyway. So it is not possible to make a sunflower bloom again the following year. If you want to have the beautiful plants in your garden permanently, you cannot avoid sowing them again every year.

Sowing the sunflower

Sunflower seeds are either bought from specialist horticultural shops or you can use the seeds that have been collected from the previous year's plant. On the one hand, it is possible to prefer the sunflowers indoors and move the young plants outdoors a few weeks later. The advantage of this approach is that the plant will then in all likelihood begin to flower earlier. On the other hand, sowing can also take place directly outdoors and at a later location. Which method you choose depends largely on your personal sensitivities.

Note: Sowing in a protected room (apartment) takes place in a planter and should be done around the beginning of March. The young plants may only be moved outside when they are strong enough and there is no more frost outside.

time

As I said, Helianthus annuus is very sensitive to sub-zero temperatures. This applies to both the fully developed plant and its seeds. The sunflowers should therefore only be sown outdoors when there is no frost or frost. Ground frost is to be expected more. Usually this is the case in our latitudes at the end of April / beginning of May. At around this time, young plants that have already been grown should also be planted outdoors. With an earlier appointment, there is too great a risk that the plant will freeze or freeze. the seed does not germinate in the soil and then rots. A later appointment, on the other hand, means that the sunflower will bloom later and also for a shorter time.

Except for perennial sunflowers

Not all sunflowers are created equal. Basically, you have to differentiate between two types. Everything that has been said so far relates to the annual sunflower, namely Helianthus annuus, which has long since become the epitome of the sunflower in our gardens. In addition, however, there is the perennial sunflowers other typesthat is a little smaller in growth. Typical species are Helianthus atrorubens, Helianthus decapetalus or Helianthus tuberosus.

What all these species have in common is that they are perennial and therefore winter hardy. The annually recurring sowing is of course not necessary for them. Rather, the plants overwinter outdoors and start growing again in spring. Incidentally, when sowing perennial sunflowers for the first time, a point in time when no more frost is to be expected is recommended.