Why Is My Broccoli Not Forming?

I have noticed that my broccoli is very leafy but not forming the broccoli itself.  This question and response came through on the Tui website we subscribe to.  I will be looking for some potash (whatever that is!) today at Mitre 10 Mega.

Hi, we are growing broccoli and it has a lot of leaves but no broccoli heart growing in the middle. We are also growing silver beet nearby, which is flourishing. What can we do to get the broccoli growing?- Andy. Hi Andy, there will be too much nitrogen rich organic matter in the vege garden – compost, blood and bone and sheep pellets – which are all great for leafy vegetables such as silver beet and spinach but not so good for your hearting vegetables such as cauliflower, broccoli and cabbage.

To fix this add potash and the best to use would be Tui Fruit and Flower – Sulphate of Potash which is a commercial grade, very fast acting and water soluble. It can be mixed with water and applied in a watering can or sprinkled around the plants and watered in. If you want to get more technical you could test your soil to find out which nutrients are deficient - soil test kits are available from garden centres and hardware stores.