Home Depot and Lowes don't tend to carry Perlite that doesn't have Miracle Grow in it. I went to a smaller nursery chain local to me and bought four cubic feet of Perlite, and used that exclusively this season with great success. I do NOT use the substrateless method, so I mixed with water until just slighltly moist to the touch and would clump together when squeezed, but easily crumble.