root bound substrates
Steve quotes Paul:
"In tanks with a large number of plants and well developed root systems,some
plants can develop symptoms of Fe deficiency. Supplementation with chellated
Fe resolves the symptoms. Cryptocorynes appear to be adept at competing for
Fe in root bound, oxygen rich substrates."
This may explain why crypts (6-7 differrent species) have completely taken
over my non-CO2 injected, low light, 70 gallon peat substrate tank after 5
years. The only other plant that is doing well is Rotala macrandra. All the
chain swords (Echinodorus tenellus) have dwindled. they used to completely
cover the bottom as a lawn. I had assumed it was crypt defensive reaction
(allelochemical). If I did not love my crypts so much, I would remove some
of the roots and thick rhizomes.
I would say that some of the other sword plants (Amazon sword, E.horemanii)
may also be adept at competing for Fe in tight quarters. These have never
minded being root bound.
Neil Frank, TAG editor Aquatic Gardeners Association Raleigh, NC USA