Then yesterday walking the dog - I noticed that a large piece of polystyrene foam had blown up on my front garden. I put it straight in the bin and continued on my walk. Just a few paces in - I thought about how very white the foam was. Perfect for deterring cabbage butterflies - further down the walk I came across a lovely branch and decided it would make a perfect polystyrene tree. So with the tree and egg shells in place hopefully the catter-pillers will be kept at bay. This morning was the first morning that I have gone out and not had to pick any off the kale seedlings!