Houston has a handful of awesome local, organic farmer's markets inside 610: Midtown Farmer's Market at t'afia, Rice University Farmer's Market, Discovery Green, Onion Creek and the Bayou City Farmer's Market off Kirby and Richmond. My beef is always that they're SO expensive, boutique and only open one or two days/week.
Enter Airline Farmer's Market - well, not really 'enter' since its the original farmer's market in Houston. AND open 7 days/week. It's miles long [I'm an exaggerator] with TONS of produce. It's cheap. It is NOT, however, local - nor organic. It's close though. And I couldn't be happier taking a Saturday morning and walking the aisles and aisles of cactus, peppers, melons, apples, pineapples, flowers; asking what this strange fruit is and trying my hand at my not-even-functional Spanish.
Pros: cheap, variety, open 7 days/week
Cons: not local, not organic