how do I stop caterpillars eating away at my cabbages

you can buy a fine mesh that prevents the butterflies laying the eggs.
as for the caterpillars you have to either spray for them or pick them off by hand and squish them.
look under the leaves for the small yelllow eggs and rub them off too.

i plant nasturiums next to the cabbages and so far i have more catrepillars on those than on the cabbages.

Yes, that's a good tip. Although they're called Cabbage White, the caterpillars actually prefer Nasturtiums to cabbages. It was on Gardener's World last week.

Very difficult if colonies are established! What I did was pour boiling water on some torn off rhubarb leaves(leave to ferment for 30 mins or so) and the resultant black liquid is highly toxic(compound of hydro-cyanic like acid) to both you and bugs(do not leave it out and store it away from children***. Spray accordingly on any plant infested with these critters or aphids!

I should add though, if you plan on eating the cabbages leave them for at least a week after spraying, thoroughly wash and boiling will neutralize any of remaining rhubarb organic pesticide!

i have had the same problem and looking for the same answer. I have just gone around them and picked them off with my fingers (i can't believe i have but hey) doesn't someone have the answer.

I've been advised to put all the side shoots of tomatoes that I've removed into a bucket of water (cut up small) and leave them for a week or so, then spray the liquid onto purple sprouting which is being attacked by catapillars. Anybody tried this? I am only at the fermenting stage at the moment!

how can i get rid of or avoid next year cabbage white caterpillars .eaten my sprout leaves, swede leaves, brocolli etc thanks rob