INDOOR WORM COMPOSTING SYSTEM EXPLAINED! The system uses three buckets. The bottom bucket is completely solid in order to capture any liquid drainage that comes from the worm composting process. The other two buckets have holes in the bottom that are large enough for the worms to travel through and for liquid to drain out. The two buckets also have very tiny holes up top that allow for natural circulation but they’re small enough to prevent the worms from getting out and to keep small bugs from