Saying you are organic in the food world won't get you very far. Certification gives you entree to higher prices for your wares, in general, so there's a clear incentive to get that seal of approval and government labeling.
The wine world seems to have thrown that model out the window. Everyone and their mother can be not only "sustainable" and "earth-friendly" but also "organic."
Witness the guidance given here on the wine country tour and reservations site GoVine. I like GoVine's functionality and it should be a great resource for helping you locate wineries with certified organically and biodynamically grown wines. Instead I visited the site this morning and witnessed this strange screen guiding me to organic and biodynamic wineries:
Unfortunately only Araujo has any certification (they're biodynamic, but are very elite, their wines allocated to a small group of buyers with unlimited budgets, and don't accept tours or visitors so you couldn't really visit).
None of the other wineries mentioned has any wines made from only certified grapes, so to call them organic or biodynamic is very strange indeed.
Unable to find a phone number for GoVine, I've emailed them about this labeling and will provide an update after hearing back from them.