An additional bottle is needed to hold the column upright and to catch drippings. These instructions are for one two-bottle column. Remove the labels from all three bottles. Cut them as illustrated, and assemble. Most columns will require air holes for ventilation, and these can be poked into the plastic with a sharp needle.
Experiments Make several identical columns and fill each with a different type of solid waste.
Layer the waste with handfuls of garden soil. Pour equal amounts of water into each column, and wait several hours for it to percolate through. If none comes out the bottom, add more in equal amounts until about a half cup drips into the base. Add water every few days. Make several identical columns, and fill each with an identical quantity of compostable waste.