Coffee grounds make a nice mulch around blueberries but spread them in a very thin layer so they don't go moldy. Coffee grounds tend to make the soil acid and blueberries love an acid soil. Some coffee stands will give away their used coffee grounds to be recycled in the garden. The caffeine in coffee grounds also repels slugs - they so hate to be perked up an prefer to remain - sluggish. Keep growing, Marianne Binetti