Planting Early York Cabbage Seeds for Bare Root Cabbage Transplants

I want to grow bare root cabbage transplants for sale and planting next spring. Can I plant Traditional Early York cabbage seeds in August? If not, what alternative would you suggest?

Early York cabbage refers to a type of cabbage with pointed heads instead of rounded ones, and there are various varieties available. 'April' can be sown in late July or early August to give plants for planting in September. 'Greyhound' seeds can be sown in late December or January in a tunnel for plants that can be planted out in late March or April for spring. Most garden centres and seed catalogues offer these or similar varieties.