Mark B. says he was always interested in making "dirt" and with plenty of people begging to get rid of their horse manure, he saw an opportunity. His system has been in operation since 2009 and from it he devised a method to collect hundreds of gallons of "compost tea" by draining the plenums. His gardening friends rave about it. The finished compost is used to fertilize his 42-acre tree farm.