eco coco
chemically inert with a low CEC and
with a minimal effect on the composition
of the nutrient. Coco contains naturally
occurring potassium, which is considered
a bonus since potassium is a major plant
nutrient; however, this needs to be accounted for in the nutritional program of
the plants. Coco also has other effects on
the composition of the nutrient solution
applied, so levels of nitrate, phosphate, calcium, magnesium and iron might need to
be adjusted to allow for these properties.
Finally, remember that coco is a living
substrate and it should be treated as an
entire eco-system consisting of beneficial
microbes that make their home in the
coco particles. This beneficial microbial
life plays an important role in soilless
systems as many fungi have a protective
effect on the plant’s root system, have
been proven to suppress plant pathogens
and have other possible benefits with
nutrient uptake and plant growth. While
other growing substrates start out as
sterile, coco is best left in its original state
or even inoculated with populations of
beneficial microbes such as trichoderma.
These populations of beneficial microbes
in coco are to be encouraged and hash
sterilizing chemicals, such as chlorine
bleach, hydrogen peroxide and even
Sometimes there is more than one use for a coconut.
boiling water, should not be used on coco
substrates for that reason.
Coco problems
All growing mediums can have their
problems. Although coco is generally
easy to use, it still needs to be monitored
for over saturation, EC and salt buildup.
Coco can look slightly dry on the
surface and still be fully moist in the
root zone, so checking the moisture
level a few inches below the surface is
recommended. Moisture should appear
when the coco is squeezed between the
fingers, but the surface should not appear wet—overly damp coco can attract
fungus gnats, as well as reduce oxygen in
the root zone.
Coco usually maintains pH within an
optimal range; however, EC can build
over time, so it should be checked—particularly under warm growing conditions.
Because of the nature of coco growing
media, the EC around the plant’s roots
might be different to that in the leachate
or the solution draining from the growing
slabs, pots or bags. However, a quick and
simple extraction sample EC test can be
carried out on coco media to determine
the actual EC around the root zone. For
an extraction test, a small sample of coco
is taken from the growing media after it
has been in use for a few weeks. Then
3.38 oz. of these combined samples is
measured out (the coco should be damp,
but not overly saturated). These sample of
coco is placed in a jar and 5.07 oz. of RO
water is added and the mixture shaken 50
times. This is allowed to sit overnight to
allow extraction of nutrient ions into the
water. The resulting mix is then re-shaken
and filtered to remove particles, and the
pH and EC can be measured from the
remaining liquid. The ideal pH range of
the extract for most crops is between 5.5
and 6.2. Ideal EC levels vary depending on the stage of plant development,
the growing environment and the crop
being grown; however, a general range
is between EC 1.0 and 2.5 (tomatoes
can be grown at much higher EC
values, particularly with commercial
crops). Larger scale growers and those
in commercial production will often
have the coco extract sent to a lab for
a complete nutrient analysis, which
determines the levels and ratios of each
of the elements in the