Not all farmers' markets in the UK are certified or monitored, and so if you're visiting one caveat emptor definitely applies—the produce you buy may not be any better than what you get at the supermarket: Consider, for example, Isle of Wight Tomatoes, one of the most established stallholders at London’s numerous farmers’ markets. It looks like a small, traditional enterprise and claims to sell its own homegrown produce. Think again. Its tomatoes, aubergines and cucumbers are bought from a separate company, Wight Salads, the bulk of whose £60m turnover comes from supplying supermarket chains.Worse, as far as many green consumers may be concerned, many of the tomatoes are actually experimental genetic crossbreeds that Wight Salads is engineering to try... More