Choose ground where other brassicas (cabbage, cauliflower, Brussel sprouts, turnips and mustard) have not been growing for at least two years. You can also grow Broccoli on an area where a previous crop has been cleared and the ground has not been dug over so that it is already firm. Alkaline soil is better than acidic soil, because this reduces the risk of club root (you can add lime in the previous autumn if club root is a problem).