Solution from 100-1 reservoirs is discharged on the surface of sand cultures (11-quart plastic buckets) by time-clock controlled air lift pumps. As the sand is flooded, the solution is returned to the reservoir by an internal siphone. The sand is alternately flooded and drained several times during each 15-minute "on" period of the clock. A bleeder hole allows the solution to drain if the clock goes off during a mid-cycle. An illustration with details of the equipment is provided.