Use of Compost as a Media Amendment for Containerized Production of Two Subtropical Perennials

Growth of Orthosiphon stamineus (cat whiskers) and Angelonia angustifolia Benth. (angelonia) was evaluated in media containing 0, 25, 50, 75, or 100% compost (biosolids and yard trimmings mixture, 1:1, by weight). Compost was added to a commercial coir-or peat-based medium. As % compost increased, pH, electrical conductivity (EC), % nitrogen (N), and % carbon (C) increased, and the initial moisture content decreased. Orthosiphon and Angelonia growth was reduced when grown in peat or coir-based media amended with high rates of compost (75 or 100%), but flowering time was generally not affected. All plants were considered visually acceptable, except Angelonia grown in 100% compost.