Growing Cosmos – Easy Annuals

Cosmos! What a stonking name for a plant evoking all the constellations in the Universe.

Growing Cosmos

Cosmos flowers are a ring of broad petals and a center of disc florets similar to a daisy.
Cosmos flowers are 2-4 inches in diameter.
There is a lot of color variation including white, pink, orange, yellow, chocolate and scarlet colors.
Most Cosmos bloom heavily but die with first frost.
Leaves are fine and delicate and therefore the plants do not over shadow other flowers.
Cosmos get quite tall at up to four feet but in rich, fertile soils tend to produce unusually tall, lanky plants.

Smaller Cosmos are lovely in containers, showing off some of the finest lacy foliage of any annual.
Sow 3mm deep in spring at 21-24C in a good seed compost. Keep soil damp but not wet, sealing in a polythene bag after sowing is helpful.
Germination usually takes 5-10 days.
When seedlings are large enough to handle, transplant and grow on in cooler conditions.
Gradually acclimatise to outdoor conditions for 10-15 days before planting out after all risk of frost 60cm apart.
Plant in a sunny spot on light even poor quality well drained soil.

Useful Links

BBC Gardeners World – Gardening site of BBC

Thompson Morgan seed varieties available

See more tips and help on Help growing Cosmos or search in the box center right.