Thin Seedlings for Airflow and Space
It’s tempting to leave all those delicate little seedlings in place after germination—but crowding leads to weak stems and less flowering overall. Thin your cornflowers to about 6 to 10 inches apart, depending on how large you want each plant to grow.
This spacing helps with airflow, which prevents mildew and keeps pollinators from getting trapped between crowded stems. I’ve noticed that spaced plants attract more butterflies—they seem to prefer open areas where they can land and feed easily. Don’t throw away the thinnings, either—try transplanting a few gently to other areas, or leave them as a sacrificial row for pests.