Good question.

I think there are a few ways to do this e.g.:

1) multiple certifications as mentioned above;

2) brand recognition / brand responsibility (the analogy is myself with the South African butter); and an option that I have suggested which amounts to

3) an/multiple environmental quotient(s) that would score higher if you have a nature reserve on the farm, use less pesticides, use compost, etc.

But, unfortunately, unless you are remarkably well informed on all the suppliers, you simply can't always know. There is an app in France that tries to do this, but I am sure that also opens the door to corruption. In the next 10 years I expect to see more such apps.

I plan on growing most of my vegetables when I'm settled down and/or joining an organic farm vegetable co-op where I can meet with the farmers and be reassured it's all grown in using safe methods and materials.

I had the pleasure of being in an organic vegetable co-op in Oregon, it's such a great idea wish it was easier to access in California.