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Abstract
Producers have experienced wide variation in yield and plant performance
under tropical greenhouse culture and have attributed this party to choice of growing media.
Chemically reactive media interact with nutrients in the fertigation solution and may improve
nutrient uptake and plant performance. This hypothesis was tested in a glasshouse trial
investigating four physically and chemically different media, including perlite (PL), coconut
coir (CC), and combinations of PL with either rice straw compost (RSC) or bagasse based
spent mushroom substrate (SMS). Treatments were planted to sweet pepper (Cv. Destra)
and fertigated with a modified Hoagland's solution. Total number of fruits per plant and yield
were measured over a 3-month production period. Plant tissue samples were taken at the
onset of flowering and at the end of the trial stem diameter, along with media pH and EC
were measured. Plant height and stem diameter was similar across media, whilst media EC
was highest for CC. This correlated with greater number and weight of fruits. Growth
parameters were lowest for PL and were indifferent between the two compost treatments.
Coconut coir showed high productivity under the tested conditions, but resulted in increased
fruit physiological disorders under the present fertigation regime. Completely organic media
may not be a suitable growing media choice for tropical production.