Abstract

In the United States commercial, ready-to-drink tea production has increased dramatically during the past 20 years, leading to an increased amount of waste. Spent tea grinds (STG) is the finely ground waste product of the tea brewing process that possesses some physical properties similar to peat moss (PM), making it a potential replacement for common substrate components such as pine bark (PB) and PM. ‘Tuscarora’ crapemyrtle (Lagerstroemia indica L. ‘Tuscarora’), ‘Chang's Ruby’ loropetalum (Loropetalum chinense Oliv. ‘Chang's Ruby’), ‘Fire Power’ nandina (Nandina domestica Thunb. ‘Fire Power’), and ‘Macrantha Pink’ azalea (Rhododendron indicum L. and Sweet ‘Macrantha Pink’) were grown in containers filled with five substrates composed of PB, STG, or a combination thereof. Substrate pH remained within an acceptable range throughout the study. Substrate electrical conductivity (EC) values were within an acceptable range at the beginning of the study, but fell below an acceptable range in substrates containing 50% or greater (by vol) STG by the end of the study. For all four species, plant growth in substrates containing up to 50% by volume STG was similar to those grown in 100% PB. Estimated leaf chlorophyll content (SPAD) of crapemyrtle, loropetalum, and azalea was the same for all treatments at the end of the experimental period.