Add some lime to the soil as Brassica`s prefer an alkaline soil

Ensure the soil after diggging over is firmed in. You can walk up and down the soil to compact it down

Keep soil moist but not to wet

Cover crops to prevent pests such as Cabbage White Butterfly (a builders debris netting is often used)

a high nitrogen feed (chicken manire pellets) when planting and again early september will increase crop size