What do I need to ask my supplier for to ensure they are certified?
If your supplier is a farm and you are buying unprocessed fibre, they should provide you with an organic certificate to recognised national or international standards (USDA NOP, EEC 2092/91 and national standards from third countries recognised in regulation EC 345/2008) from a IFOAM accredited or internationally recognised certifier (ISO 65).
If your supplier is a processor or trader, they should provide you with a GOTS certificate and schedule (product list) from a GOTS recognised certification body. For a list of approved certifiers see here http://www.global-standard.org/certification/approved-certification-bodies.html.
In many cases Transaction Certificates (TCs) are also required. These list specific products delivered in specific consignment from one company to another.