You can buy or sow Cosmea if you want to bring these plants into your garden. Buying is easier, but sowing is also relatively easy to do and is a lot of fun.
When and how can you sow Cosmea?
Cosmea can be sown indoors from the end of February or outdoors from mid-May. The small seeds should be distributed in nutrient-poor growing substrate or sandy soil and only covered thinly. At a germination temperature of around 20 °C, the first seedlings appear after 14-21 days.
If you use seeds that you have collected from old plants, then you are working with a “magic bag”, so to speak, because you do not know which genetic characteristics of the parent plants will prevail in your young plants.
Sowing in the house
In March or April the time has come to sow the Cosmea on the windowsill or in the warm greenhouse. Fill a container with nutrient-poor growing substrate or soil mixed with sand. Then sprinkle the small seeds on top and some soil on top.
Wet the whole thing carefully and regularly with a water sprayer (€9.00 on Amazon) and place the growing container in a warm place, preferably on the windowsill. At around 20 °C the first seedlings will be visible after approx. 14 – 21 days.
Sowing outdoors
If you would like to sow the decorative basket directly outdoors, then you will have to wait until mid or end of May. Ideally, you should only sow after the ice saints so that your seedlings do not freeze. Here too, the soil should be low in nutrients and kept evenly moist. However, the start of the flowering period is postponed by a few weeks because the plants first have to grow.
Undesirable propagation by self-seeding
Unlike plants, Cosmea seeds are hardy. They can tolerate frost and will germinate easily next spring. New cosmos plants often grow unplanned in the old location, even if this bed is now intended for other plants. Weeding can sometimes become annoying. However, you can also simply relocate the unwanted plants to another location.
The most important things in brief:
- very small seeds
- Self-seeding often
- Seeds can be collected and dried
- Sowing indoors from the end of February
- Sowing outdoors from mid-May
- only cover thinly with soil or substrate
- Germination temperature: approx. 20 °C
- Germination time: 14 – 21 days
Tip
If you want your Cosmea to bloom early, then you should prefer the young plants indoors and not sow them outdoors.
