Not much experience here with bone meal. I've read that it attracts critters so I'm reluctant to use it much.
I do use all of our used coffee grounds in the garden, just about anywhere. I sometimes add them to the compost, sometimes just fling them into a flower bed or even the lawn. My feeling is, if nothing else, they increase the organic matter in the soil so why throw them in the trash.
I've read that most N washes out in the brewed coffee and therefore the used grounds are a very weak N source. For a few years I was getting larger amounts of grounds from a local coffee shop- about 2 or 3 five gallon buckets of them a week. Added to the compost, they made it HOT. That tells me there must be a fair amount of N left in those grounds. Sadly, I lost my source when the coffee shop closed.
Karen
