Cornflower 'Blue Diadem'

1200 Seeds

How to Seed Cornflower ‘Blue Diadem’ (Centaurea cyanus)

1. Sowing Time:
   Sow directly outdoors from March to May for summer flowering, or in autumn (September–October) for earlier blooms the following year. Cornflowers grow best when sown directly into the ground.

2. Sowing Depth:
   Sow seeds 0.5–1 cm deep in finely raked, moist, well-drained soil. Lightly cover and firm down gently.

3. Soil:
   Prefers well-drained, moderately fertile soil. Avoid very rich soil, which can cause excessive leaf growth and fewer flowers.

4. Light & Temperature:
   Choose a sunny, open position. Ideal germination temperature is 15–20 °C (59–68 °F).

5. Germination Time:
   Seeds usually germinate within 7–14 days.

6. Thinning:
   When seedlings are large enough to handle, thin them to 15–20 cm apart to allow strong, bushy plants.

7. Growing Tips:

   • Water regularly until established, then only during dry spells.

   • Deadhead spent blooms to encourage continuous flowering.

   • The variety ‘Blue Diadem’ produces rich, deep blue double flowers, excellent for cutting and attracting bees and butterflies.

   • Cornflowers prefer full sun and are perfect for borders or wildflower gardens.