Perlite is the most commonly used additive for increasing soil drainage. It is volcanic glass that forms when glass literally pops like popcorn under super-heated temperatures. It is extremely light and porous! It works wonders on species like Begonias that like a fluffy, quickly draining soil mixture. This perlite in particular is an extra fine grade!
A 2 quart bag can roughly fill one and a half 6" diameter nursery pots.
A 1 quart bag can roughly fill one and a half 4" diameter nursery pots.
All soil amendments ship in a biodegradable bag.