In the years 1996-1998 in the Sewage Treatment in Hajdów an experiment was set up in order to determine the optimal number of plants and the method of proliferation of Sida hermaphrodita R. on sewage sludge. The cultivation of Sida was carried out on especially prepared plots with an added 50 cm thick layer of sewage sludge. Two methods of plantation establishing (propagation) were used - generative and vegetative. Three plant densities were used per 1 ha: 3 kg of seeds or 33,000 seedlings; 6 kg of seeds or 50,000 seedlings; and 9 kg of seeds or 100,000 seedlings. Higher yield of stems and greater amounts of Fe extracted from the sludge were obtained from the vegetative plant propagation. In the conditions of greater number of plants, considering the stems yield, Sida took from the sludge more Co, Fe, and Ni. The three-year long cultivation of Sida hermaphrodita caused positive changes in the structure of the sewage sludge.