Catch crops for brassicas

[Mikey & Annie]

As our kitchen garden is small we try to use every inch of space to grow food. Can anyone recommend what can be used as a catch crop between cabbages, caulis, kale etc? Other info from the internet suggests beetroot, of which we already have enough sown, or small lettuce but we have a snail problem and are led to believe that the snails attracted by the lettuce then go on to munch the brassicas.

[Organic Kitchen Gard]

How about radishes, rocket, or oriental greens? They are all brassica family as well so will fit in with your crop rotation.
I think if you have slugs/snails they'll find the brassicas anyway without the help of lettuces (unfortunately!) but I have found pigeons more of a problem with my newly planted brassicas and that once they're establshed there's no slug problem. But I do keep them covered with Enviromesh to keep the birds and the cabbage root fly out!