Optimizing the Physical and Chemical Properties of Growing Media for the Rooting of Cuttings ofAcacia Mearnsii(de Wild)

Rooting media were evaluated to identify problems contributing to poor rooting. Seven media combinations of coir and perlite were investigated, including two sources of coir (‘CG’ and ‘GS’). Final rooting results showed that the 2:1 (‘CG’ coir: perlite), with or without Osmocote® Start, and the 50:50 (‘GS’ coir: perlite) medium supported the best rooting results (19.49%, 19.79% and 17.11%, respectively). Differences between the two sources of coir (‘CG’ and ‘GS’) were evident, with ‘GS’ coir having higher electrical conductivity (EC) levels (0.35 versus 0.28 dsm−1). Greater rooting was also observed in the medium with the ‘CG’ coir, when comparing the 2:1 (‘CG’ coir: perlite) with Osmocote® Start and the 70:30 (‘GS’ coir: perlite) medium. A decline in rooting was observed as the ratio of coir to perlite increased. The media combinations that supported the most rooting had air-filled porosities between 25 and 35% and ECs between 0.2 and 0.4 dsm−1 at Week 0.