I try to keep them on younger grass before it gets woody. I have not tried keeping them on different types of grasses to see how they do and taste.
I have tried old apples and pitted peaches, onions and garlic, and oranges and grapefruits as daily snacks. These things did change there flavors and I will never try the onions and garlic again. The citrus I will do again if I can find a large amount of old citrus and will have room in my freezers.