Growth of Foliage Plants in Composted Raw Sewage Sludge and Perlite Media

Abstract

Raw sewage sludge compost was tested as a major component of media for the production of foliage plants. Each of 4 previously screened compost fractions was blended with 0, 20, 40 or 60% perlite (v:v) and to half the pots a slow release fertilizer was added. Top dry weight of Tradescantia fluminensis (Wandering Jew) was greatest in mixes with low soluble salt levels and high levels of air-filled pore space. Mixes exhibiting these qualities contained a high percentage of perlite and/or large compost particle sizes. Fertilizer application did not significantly increase dry weights. In a second experiment, Plectranthus australis (Swedish Ivy), Tolmiea menziesii (Piggyback), Sedum lineare var. variegatum (Star Sedum), and Wandering Jew were grown in commercial mixes and 2 superior sludge compost-perlite mixes (SP) at 3 fertilizer levels. While all species grew well in commercial mixes, in SP mixes growth was comparable only for Wandering Jew or for Swedish Ivy or Sedum grown in the coarser compost mixture.