Not all of the food from my CSA is certified organic, but that's primarily because the certification process is rather a lot of work for a small farm like Featherstone.
Eating food that comes from a specific place changes your relationship to the cycle of production. For the last two weeks I didn't gotten a box of produce from my CSA, but have instead been reading their newsletters about recovering from the destructive floods that hit southeast Minnesota last month. Compared to others in the area they made out okay, but the tales have been at times heartbreaking. I look at my table and know that no more heirloom tomatos are coming after I eat this last one, because a scant hundred miles from here a torrent flattened the field where they had been growing. I think that most food consumers do not have this experience.
Here's an interesting conversation with Michael Pollan on organic farming from MPR last year. Shorter Pollan: modern "organic farming", and Whole Foods with it, is kind of a crock, but not entirely useless. You should really just buy local produce from your farmers' market and ask how it's grown if you care. Which you should.
In the case of a CSA I'm getting food not just from the local farming community, but from a specific farm and farmers, who I know by name, who tell me in detail how the food is grown, and what hopes and dreams they have for this food and this farm. For two weeks it felt like I was living a stopgap diet, stretching the last of the sweet corn and cherry tomatoes until the fresh bounty of last weekend's box finally arrived.