How to Make a Self Watering Container
Excess black water from septic tank goes into "self-watering container"-style leach field, where green manure mulching crops such as comfrey are grown. Green manure mulching crops are then cut down and distributed all over the garden as fertilizer. Leach field is designed large enough to accommodate as much liquid as will build up in the leach field over winter, when plants don't consume as much water as in summer.