What should it mean? Is it purely subjective? Maybe, I don't know. These questions are purely rhetorical. Does green mean sustainable?
Is growing organically being green? I think it depends. If I'm using something like Neem, which comes from trees in the Indian sub-continent (Wikipedia), and it must be shipped thousands of miles, is that really the best use of resources? Even if I'm using it on an organic garden in Kentucky? Or bat guano? Disturbing bats causes their numbers to decline, so is that sustainable or green?
Buying bagged compost that was made in Florida? Is that green? Is that sustainable?
What about lawn mowing, string trimmers, and leaf blowers? Today's mowers are gas guzzlers. They consume a large amount of energy and pollute our air with fumes and noise. Should we change the way we mow and trim? Should we demand cleaner gas-powered tools?
Is using manures on your gardens being green? Even if some can potentially carry bad, bad organisms that make humans sick?
I don't know the answers to these questions, they are more to ponder. To think about. To maybe change your idea of green.