Use Super Hydro indoors when X-treme drainage is critical! This formula is proven in grower trials to drain twice as fast as ordinary potting soil or growing mixes, so you'll never have soggy soil again! Super hydro is studded with Pro grade perlite for never-fail drainage and aeration. The formula is myco-active; we use only high-functioning endo-mycorrhizae strains...no useless ecto "filler" strains which will colonize only certain types of trees like spruce and fir. Super hydro is X-tra bio-active, rich with earthworm castings. Grow like the pros...with confidence!