Food from used water : making the previously impossible happen

In rural areas where water is scarce, household wastewater (grey water or sullage) can be used to grow vegetables in “tower gardens”. These are columns of soil that fill a bag made of shade netting. Wastewater is poured into a central stone packed drain, which distributes water evenly in the “tower”.  Tests with different designs in South Africa revealed that a mixture of six parts of soil, four parts of manure and two parts of wood ash give good results. Careful packing of flat stones or building rubble for the stone filling ensures good water distribution. The towers are ideal for growing leafy vegetables like spinach and require little labour or attention if properly designed. The inspiration for the South African “tower gardens” came after a small group of people saw them in Kenya on a trip to assess treadle pumps. In South Africa, the first “tower gardens” are in use in one site in the Eastern Province (Ndonga area) and two sites in Limpopo Province (Nzhele valley and Makuleke).