I put a ring of BFB around mine when I plant them out I have an idea they do not like climbing over it. Also the plants take off quickly. Also plenty of manure, and a mulch of grass clippings if I have them.
I have also got debris netting, but butterflies managed to get in but not too bad I think they will recover. The debris netting also keeps the wind off. Some of my sprouts are 5 ft tall.
I have had success in the past with planting them within a ring of phacelia
I have trouble with tea leaves so have given up on winter cabbages. Sometimes I only manage two out of a batch of twelve, so it is not worth it.
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