Advertisement Imagine my confusion, I mix Eco Earth and sand for my hermit crabs and find it retains moisture quite well, but when it comes to desert Tarantulas I am in a quandary. “For desert spiders use peat or fine bark chips mixed 50/50 with clean sand,” pg. 24 Tarantulas and other Arachnids by Samuel D Marshall “Fine sand is not recommended,” pg. 141 The Tarantula Keeper's Guide by Stanley and Marguerite Schultz Being unsure of the proper rout to take for housing desert Tarantulas like an A. chalcodes I am seeking a consensus of the learned AB contributors as to the best substrate to mix for these little guys. .