Noordermarkt

Nice, but quite expensive (and it's not an organic market)

The Nordemarkt is a boerenmarkt (farmer's market) but not an organic market, that is, there may be some stalls that sell organic produce (just as in any other shop or market), but there is no requirement for any of the stalls to do so.

The only organic market in Amsterdam (on the same scale as the Nordemarkt) is the Nieuwmarket on Saturdays (10-4).  It is also generally a bit cheaper than the Nordermarkt because it is less touristy (the Saturday Nordermakrt is quite famous and popular for various other stuff, i.e. antiques, second hand books and clothes, ceramics, etc.).

I have no vested interest in the Nieuwmarkt, but a lot of people in Amsterdam are under the impression that the Nordermarkt and the Nieuwmarkt are both organic, but this is not true, and people tend to get misled.