Know
What You
Grow In
by Dr. J. Benton Jones, Jr.
Many rooting media contain
some of the elements essential
to plant growth. As Dr. J. Benton
Jones, Jr. explains, knowing
what’s already in your medium
can help you choose the nutrient
solution that will help maximize
your plant’s health…
Many commonly used rooting media are derived
from naturally occurring substances; therefore, they
contain some, or many, of the essential plant nutrient
elements. Here, samples of rockwool, perlite and coir
were heated in aqua regia (a mixture of concentrated
hydrochloric and nitric acids). Perlite did not go into
solution, but the obtained digests of rockwool and
coir were assayed for their elemental contents by ICP
spectrometry. The results are given in the table one.
Being natural products, these rooting media will
have differences in elemental content depending on
the composition of the source material. Therefore,
there is probably a “batch effect.” For rockwool, for
example, the chemical composition of the source
mineral, as well as the fluxing agent (limestone), will
determine the final product’s elemental content;
while for coir, the chemical environment associated
with the production and processing of the coconut
fiber will determine its element content.
96
Maximum Yield USA | September 2012