Whilst cauliflowers are hardy little plants it’s still worth protecting the heads from frosts and cold weather by pulling the leaves over the top and tying them in.
It really is as simple as it sounds – if you can see the cauliflower heads on your plants, then you want to keep them protected from the elements so that when you harvest them they are still a lovely, creamy white. All you need to do is get a length of twine, pull the outer leaves around the head (don’t worry if the stalk breaks slightly) and tie them so that they keep the fluffy white cauli covered up until you’re ready to harvest it.
Incidentally, it’s good to do this when growing cauliflower in spring and summer as well to stop them from getting scorched by the sun.