Comparison of Salvia Growth in Seaweed Compost and Biosolids Compost

Abstract

Salvia ‘Red Hot Sally’ (Salvia splendens F. Sellow ex Roem. & Schult.) shoot dry mass and number of flower spikes was significantly greater in substrates containing compost made from biosolids and yard trimmings (SYT) than in substrates containing compost made from seaweed and yard trimmings (SW). Initial substrate electrical conductivity (EC), nitrogen (N), phosphorus (P), and potassium (K) concentrations also were greater in substrates containing SYT than in substrates containing SW. Salvia shoot dry mass and flower number increased as the percentage of SYT compost increased from 0 to 60% but decreased at 100% SYT. Initial EC levels in 100% SYT were more than twice as high as the levels measured in the other percentages. Shoot dry mass and number of flowers of plants grown in 30, 60, and 100% SW, however, was similar to plants grown in 0% SW. There were no differences in plant quality rating among the treatments and all salvia plants grown in both compost products were considered saleable.