Particle Densities of Horticultural Substrates

The heterogeneity of horticultural substrates makes basic physical characteristics, such as total porosity and particle density, difficult to estimate. Due the material source, inclusion occluded pores, hydrophobicity, density values reported from using liquid pyknometry, vary widely. Gas pycnometry was used determine coir, peat, perlite, pine bark, wood substrates. Further precision examined by gas species separation size. calculated densities for each determined He, N 2 , air were relatively constant varied little despite used. Particle size affected measured perlite bark but minimal with wood. Reducing removed more pores increased. Given small variability, use obtained provides repeatable, precise measurements substrate porosity.