Just use a layer of lava rock under your soil mix...1 bag can spread out to several pots. then like DP said perlite and peat is what I add to my sterile soil

p.s.moving this to indoor growing.
latewood Reviewed by latewood on . Lava rocks I saw before somebody wrote about how you should put lava rock at the bottum of everything, for draining and for minerals. i was looking and i found some, but it looked like it was more for grills and charcoal. does anybody know if this is good or not? thank you. Rating: 5