Decanter has reported that people have been purchasing vineyards in Washington state to convert them to marajuana farms. Apparently, selling marajuana is more profitable than selling grapes. Such a practice certainly gives new meaning to planting cover crops. Of interest, marajuana plants require significantly more water through irrigation that grapevines do, which is what tipped off authorities to the problem.
While this issue doesn’t appear to be widespread, to me, the real crime is turning a functioning vineyard into something other than a vineyard.