Comparison of composted hardwood and peat-based media for the production of seedlings,foliage and flowering plants

The germination and growth of Brassica oleraceae var. capitata, Lactuca sativa and Matthiola incana were not significantly affected by replacing peat in their growing-media with sawdust (Eucalyptus and Tristania) composted with urea (2.6 kg/m³) and other fertilizers for 6 weeks. Two thirds of the peat in the media could be replaced with sawdust before the germination or growth rates of Papaver orientale or Senecio × hybridus were significantly affected, while half of the peat could be replaced with sawdust before Viola × wittrockiana was significantly affected.The growth rates of Adiantum raddianum, Asplenium nidus, Coleus blumei, Dieffenbachia picta, Nephrolepis elata, Peperomia scandens, Philodendron sellonium × specciosum, Pilea cadleri, Saintpaulia and Schefflera actinophylla in media containing 50–80% composted hardwood sawdust were equivalent to, or significantly better than, growth in media containing an equal percentage of sphagnum peat and receiving the same level of liquid or slow-release fertilizer. Substitution of sphagnum peat with composted sawdust reduced the leaf area and dry weight of Impatiens walleriana, possibly due to a small decrease in the available water in the media. It did not, however, have a significant effect on either their number of flowers or their surface area. The growth of Pilea and Saintpaulia was best where the media contained equal percentages of sawdust and peat than where either was used alone.