Firstly, this wasn't exactly a "tax" because it wasn't meant to raise government revenue. And it wasn't Obama's proposal. In fact it's a fee to be paid by growers, not sellers, who "requested" the idea in 2009.
I've had vegetable gardens in the past, but this is different. This year, I have a market garden, and I'm selling vegetables at a farm stand. It's supposed to be kind of a part-time gig, but that, as you can imagine, is a joke.