Don't you hate it when that happens?
If you are going to Home Depot, get a bag of Miracle-Gro Cactus Palm and Citrus Soil and a bag of perlite. Add at least 1/3 perlite and 2/3 Cactus, Palm and Citrus Soil together for you potting medium. Find a terracotta pot that is wider than tall. Not too big - maybe give the cactus an extra inch all the way around. The problem with sand is that it packs and does not aid in drainage but may make drainage more difficult.
I think it's great your GS is into cactus. Think of all the other things he could be into. No, maybe don't think about that.
Daisy
