Loosen and Enrich the Soil
Cornflowers aren’t terribly fussy about soil, but if you want them to grow huge and bloom prolifically, give them a good foundation. Loosen the top few inches of soil and mix in compost or aged manure to improve drainage and fertility. Sandy or loamy soil is ideal, and they prefer it slightly alkaline.
By prepping your soil ahead of sowing, you allow roots to establish quickly and deeply. Healthy roots support taller plants and fuller flowering, and the added organic matter invites beneficial soil insects and microbes that improve nutrient uptake. I’ve found that the healthier the soil, the more self-sufficient the plants become through the summer!