The term 'organic' is legally defined one, so in order to describe or sell a wine as 'organic' the vineyard the wine comes from must have been inspected by a recognised organic certification body. Furthermore, organic wines must identify the name of the certification body on the bottle label (examples include Ecocert, Nature et Progres or Terre et Vie from France, or The Soil Association in the UK). This allows those thinking of buying organic to check whether a vineyard claiming to be organic really is certified as such. The term for this type of labelling is 'transparency'. 

Some wine growers who say that they practice organic methods choose not to become certified because certification involves fees and paperwork - and a 100% commitment to more sustainable methods, all the time. At Vintage Roots we have decided only to sell wines from growers who have paid for and achieved certification, giving them the legal right to describe their wines as 'organic' or 'biodynamic'. Holding certification for the wines that we sell strengthens our confidence that no chemical fertilisers, synthetic pesticides, herbicides or fertilisers have been used on the vines.
 

What is an Organic Vineyard? (A Bug's Eye View)
What are Vegetarian and Vegan Wines?
Organic Wines Versus Wines Made From Organically-Grown Grapes
What is Reconversion?
What are Biodynamic Wines?
GMOS in Wines
To Yeast or not to Yeast, That is the Question