keeping with the flow
roots again. Since the cost of the nutrients are usually the primary concern in
regards waste, and recirculation would
seem to be the better system.
“In recirculation
systems, the nutrients
that are returned to
the water-nutrient
reservoir have actually
been chemically
modified through the
action of the growing
medium and biological
activity there.”
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Maximum Yield USA | September 2012
The significant disadvantages of recirculating systems, however, include an
increase in the potential for disease (root
rot) and the degradation of the nutrients as they are recycled. Consider this:
When solution is applied and reapplied
many times, the opportunity for a weaker
plant to develop and produce some type
of fungal, viral or bacterial pathogen increases—often substantially. This increase
is proportional to time or the number of
recirculations; so, the longer a particular
crop is being cared for, the greater their
risk for some sort of root-related disease.
Unfortunately,
this also means
the greatest risk
is at the end of
the growth cycle
when the crop is
ready for harvest.
Drain-to-waste
systems, on the
other hand, apply water only
once before
allowing it to
drain off. This
helps prevents
a disease in one