Moderate Increases in Substrate Packing Density Can Improve Petunia Root Development

Greenhouse horticulture relies on manual labor for plug transplanting, which is subject to variability in substrate packing density. Little research exists on the effect variable substrate packing density has root morphological development. Petunia hybrid ‘Supertunia Honey’ plugs were grown in peat-based substrates packed at four densities (0.08, 0.10, 0.12, and 0.14 g·cm −3 ). The results indicated that root development was improved with moderately increased substrate density.