BGA chairman Phillip Effingham and vice-chairman Alistair Ewan both painted a bleak picture when they spoke at last week's Rijk Zwaan brassica conference, in Boston, Lincolnshire, as part of the Brassica Year 2008 promotion.
Effingham said costs included a sharp rise in the price of fertiliser, polythene, land rents and labour.
He said: "The industry is in denial and unless we get a significant increase in price for our produce, brassica production in the UK will become unsustainable."
Ewan said there is a reduction in demand in Scotland for processing and freezing crops such as broccoli due to companies buying cheaper products from eastern Europe.
But he expressed hope that the reduction in the value of the pound against the euro might encourage some processors to return to British products.