Ciao, It's simple: follow the path on the site home page: join - do you want to become a host?
in this way you can have the information you want.
We have never asked for certification (which we consider a minimum requirement) but the commitment to practice natural agricultural techniques. Many hosts practice techniques that are much better than required by certification standards. Above all we have always considered organic farming as a life choice.
The host will be visited by one of our coordinators and sometimes invited to attend a local meeting. Once accepted, the wwoofers will certify every day the consistency of their behavior.