Reusing garden media is not always the best choice,
however, as certain growing mediums—such as
rockwool—are not very suitable for repeated use. Any
plant material or media that has been exposed to a
pathogen should also be removed from the system in
order to prevent the disease from spreading. For example, a single plant infected with the dreaded tomato
mosaic virus can infect growing media and future
crops grown in it for years; hence why infected plant
material and media should be isolated and destroyed.
Another concern to be taken into consideration is
that several chemical sources of nutrients can leave
heavy metal and salts behind after macronutrients have
been used, and this can result in slowly rising amounts
of both toxins over a period of years. This problem
is faced by soil fields where long-term heavy use of
chemical fertilizers has damaged the natural microflora-based nutrition cycles.
Still, even with the above considerations in mind,
there are many times when reusing media and leftover plant material not only makes sense from an
economic standpoint, but from a nutritional one
as well. During growth, plants distribute the nutrients they absorb throughout the plant, not just in
the harvested portions. As such, there is a quantity
of valuable nutrients still locked in the plant material and roots, and the media attached to the roots.
Any plant material or media
that has been exposed to
a pathogen should also be
removed from the system
in order to prevent the
disease from spreading.
Maximum Yield USA | September 2012
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