Germination and Growth of Seedlings in Peat-Based Substrates Processed Dairy Manure Solids

Peat is the most widely used substrate in greenhouse production, but interest in alternative substrates has increased recently. The objective of this research was to compare germination and growth of seedlings in sphagnum peat-based substrates amended with "Nature's Natural" (NN). NN is a processed dairy manure product. Substrates were used contained varying proportions of peat or NN: 0% NN and 100% peat; 20% NN and 80% peat; 40% NN and 60% peat; 60% NN and 40% peat; 80 % NN and 20% peat; 100% NN and 0% peat. Days to germination were recorded in three species: impatiens (Impatiens walleriana), vinca (Catharanthus roseus) and tomato (Lycopersicum esculentum), and shoot and root dry weights were determined after 3 weeks. For impatiens and vinca there was no difference in days to germination among substrates. For tomato, days to germination was lower for NN-amended substrates than for the 100% peat substrate. For all species, shoot weight did not differ between NN-amended substrates and the 100% peat until the percentage of NN was 60% or higher, at which point shoot weight decreased. For impatiens and vinca, root weight was not different for NN-amended substrates and the 100% peat until the percentage of NN was 40% or higher, at which point root weight decreased. For tomato, root weight did not differ among the root substrates. It was possible to use NN as a partial substitute for peat in the germination substrate. Maximum germination and growth occurred where NN comprised 20% to 40% of the substrate.