Evans' experiments showed that Growstones had an AFP higher than that of both peat and perlite. Additionally, when added to peat at a concentration of at least 15%, Growstones increased the AFP of the resulting peat-based substrate.
"Growstones can be used in a similar manner to perlite and PBH as an aggregate to increase AFP of peat based substrates", Evans said. "The primary differences were that, at concentrations of 25% or more, GS resulted in a higher AFP than equivalent perlite-containing substrates. Also, substrates containing 20% or more GS had a higher water-holding capacity than equivalent perlite- and PBH-containing substrates, and GS-containing substrates had a higher bulk density than equivalent perlite- and PBH-containing substrates."
All GS-containing substrates had physical properties within recommended ranges. Vinca, impatiens, and geranium plugs grown in GS-containing substrates were comparable to plants grown in equivalent perlite- and PBH-containing substrates.
Evans said that the experiments showed that Growstones can be successfully used as a component for substrates used in greenhouse crop production.
|Contact: Michael W. Neff|
American Society for Horticultural Science