Bedding plant growers have the opportunity to utilize composted urban waste as a component in bedding plant media. Growth of Dianthus chinensis L. (dianthus) and Petunia × hybrida Hort. (petunia) was evaluated in media with 0, 30, 60, or 100% compost made from biosolids and yard trimmings. Dianthus and petunia shoot dry mass, size, and height increased as the percentage of compost in the medium increased from 0 to 60% but decreased at 100% compost. However, dianthus and petunia growth was greater in 100% than 0% compost. Initial nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and soluble salt concentrations linearly increased as the percentage of compost in the medium increased from 0 to 100%. Soluble salt concentrations in 100% compost were 28× greater than in 0% compost and 2× greater than in 30 and 60% compost. Media containing compost made from biosolids and yard trimmings produced larger dianthus and petunia plants than plants grown in peat, vermiculite, perlite medium. The best dianthus and petunia growth was in the medium containing 60% compost.
Florida Agricultural Experiment Station journal series no. R-05677. I thank Maria Bravo, Gary Gorecki, and George Fitzpatrick for their technical assistance, the Solid Waste Authority of Palm Beach County for the compost product, and Lovell Farms, Miami, FL, for the plant material. This work was supported in part by a grant from the Center for Biomass Programs, University of Florida.