Cornflower: Sowing, planting and harvest calendar
When and how should you sow cornflowers outdoors?
Sow cornflower, Centaurea cyanus, directly where it will grow in a sunny, freely draining position. This is an annual flower, not a blueberry bush. Spring generally suits outdoor sowing; autumn establishment depends on a mild climate and suitable soil conditions. Avoid frozen or waterlogged ground and dry spells that would prevent even emergence.
Remove competing weeds and prepare a fine surface without large clods. If the soil is dry, water before sowing and let the moisture soak in. Make a shallow drill, distribute seeds without crowding and lightly cover with fine soil, following the depth specified for the seed lot. Full sun suits plant growth; that does not mean the seeds must remain uncovered to receive light.
Firm gently and maintain enough moisture during emergence, using a fine spray that does not move the seed. Mark the row to recognise seedlings. Thin after true leaves appear, according to the variety's mature spread, instead of placing every seed 30 or 40 cm apart. Weed carefully around young plants. Naturally good drainage matters more than automatically adding compost or routinely acidifying the soil.
When does cornflower bloom and how can you prolong flowering?
