Hydrolife Magazine February/March 2017 (USA Edition)

grow
my view is that our favorite plant likely
falls on the higher side of the continuum,
as cannabis is a highly productive annual
capable of explosive growth.
Another consideration is that, over time,
many C3 plants fail to maintain the
productivity gains that they initially
experience with CO 2 fertilization.
Understanding this goes back to
RuBisCO activity.
Scientists studying the phenomena
have found RuBisCO levels in many
plant species lowers over time in
response to elevated CO 2. This occurs because
the environmental cues that drive
RuBisCO production are suppressed
under enhanced CO 2 conditions. The
degree to which acclimation to enhanced
CO 2 occurs is species-specific, and few
studies have evaluated this response
at CO 2 levels higher than 700-800 ppm.
In cannabis, it may be more effective to
gradually increase CO 2 concentrations
over the crop cycle, as opposed to raising
them to the highest level immediately.
As cannabis legalization continues to
progress and the markets in legal states
mature, the physiology of cannabis will
hopefully be studied to the same degree
as other crops. With these efforts will
come a better understanding of how to
best use CO 2 fertilization in cannabis
cultivation. Until that time, my advice
is to enhance bloom in the 1,200-1,600
ppm range, with 1,400 ppm as a good
rule of thumb. If you are running CO 2
in the vegetative phase, I don't recommend
exceeding 800 ppm. This level
provides your vegetative plants with
a good boost and ensures that they
see a significant benefit as they move
into higher CO 2 in flower. If able, I also
recommend experimenting with different
levels of CO 2 fertilization and with
gradually increasing CO 2 concentrations
across the bloom cycle.
Daniel Banks is a consultant and
passionate cannabis enthusiast based
in Denver, Colorado. He completed
a bachelor's degree in Horticultural
Science and a minor in Entomology at
Colorado State University in 2012. His
company, Next Generation IPM LLC,
provides Integrated Pest Management
focused consulting to licensed
cannabis cultivators.
“AS WITH MOST things,
too much CO 2 can
have negative effects,
leading to lower yields
and leaf death at
extremely high levels.”
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grow. heal. live. enjoy.
myhydrolife.com