I won't spend much time arguing with Flanagan's non-sequitor; instead, I'll link you to some excellent and much-expected critiques. First, there's Chef Ann Cooper's response here. Hers is particularly important to read because she's spent much of the past 10 years advocating for school gardens and increased education about food issues in our elementary schools. Next, there's Tom Philpott's response, where he draws on his experience as both a farmer and an educator to pick apart Flanagan's rationale. My favorite response is from Philpott's fellow Grist writer Kurt Michaael Friese here. In it, he writes three sentences that sum up our view on the matter verbatim.
There is nothing taught in schools that cannot be learned in a garden. Math and science to be sure, but also history, civics, logic, art, literature, music, and the birds and the bees both literally and figuratively. Beyond that though, in a garden a student learns responsibility, teamwork, citizenship, sustainability, and respect for nature, for others, and for themselves.
Flanagan's article is particularly salient to us, as we are in the planning stages of collaborating with local school systems to implement school gardens into their curriculum. We are very close to establishing a number of raised bed plots at Hillsboro Elementary, where almost half of the student population (49.5%) qualifies for free or reduced lunch. Gardens can be exceptional learning tools for our youth, and if more people like Flanagan actually spent time in a garden, with children, they would realize it immediately.