When I juice wheatgrass with a (Green Power or Green Life), I get a lot of foam. How can I avoid this?

You can reduce the foam a number of ways
1. Dunk the wheatgrass in cold water before juicing it.
2. Put a carrot or celery, or other veggie through the machine after the wheatgrass.
3. Drop a few drops of flax oil into the gears before juicing the wheatgrass.
Also try using the fruit attachment and only tighten it halfway. (the new manual has it backwards) Also, try spraying a mist of cold water on the top of the foam helps it to settle down.