Charlie Pridham wrote:
Then planting something smelly like onions or garlic near carrots etc
disguises the smell of carrots and distracts carrot root fly from finding
your carrots

We have a load of left over garlic from last year that is sprouting and we
were going to companion-plant it with something on the allotment. Nick
thinks potatoes and peas are the way to go. Although since we don't tend to
get pests in our potatoes anyhow, I'm not sure what he's trying to ward off
....

Probably the best bet for brassicas is to cover them in net or fleece to
stop the butterflies

And pigeons.