Efficacy of Ground Fresh Rice Hulls as a Substrate Component for Greenhouse Crops Production Using Overhead and Ebb-and-Flood Irrigation Systems

Geranium 'Score Red Deep' (Pelargonium x hortorum) plants were grown in ground rice hull-containing substrates. All substrates contained 20% (v/v) perlite. Additionally, substrates contained 0%, 10%, 20%, 30%, 40% or 50% (v/v) ground rice hulls with the remaining volume being Canadian sphagnum peat. Plants were grown on either expanded metal benches or ebb-and-flood benches and fertilized with 50, 100 or 150 mg.L-1 N at each irrigation. For all substrates, irrigation methods and fertilizer concentrations, plants grown on ebb-and-flood benches flowered sooner, were taller and had higher dry shoot and root weights than those grown using overhead irrigation. As the amount of ground rice hulls were increased, days to flower increased and height, shoot dry weight and root dry weight decreased. As the N concentration increased, days to flower decreased and height, shoot dry weight and root dry weight increased.