This new article talks more about the nitty-gritty about how to be listed as a Fair Trade coffee grower. For one, You need to be in a co-op. If you are an independent farmer you are ineligible. If you are in an African tribe, you aren't in a co-op because your society doesn't work that way. Don't apply, you aren't eligible. It also costs between two and four thousand dollars, and a percentage each year of the profits.
The price paid for Fair Trade doesn't actually have anything to do with quality, only that the growers meet someone's standard of "fair." Starbucks, who is interested in buying good coffee for as cheap as they can get it, spend just a few cents less a pound than they Fair Trade co-ops get. Paying a premium for good quality encourages good quality and penalizes poor quality. Paying a premium for particular business practices encourages those practices and penalizes different practices. Since I don't believe a co-op is fundamentally better than a tribe or independent growers, Fair Trade is subsidizing non-optimal practices.
[1] Give yourself 5 points if you asked "harmful to whom?" The answer is harmful to the people who can't get into the sweet deal, and those hit with unforseen consequences to bad economics. For an excellent book about unforseen economic consequences to bad policy, read Henry Hazlitt's Economics in One Lesson.