Hydrolife Magazine June/July 2016 (CAN Edition)

grow
The key metric in cannabis cultivation
is yield of dried flowers and it is
the primary focus for every gardener
regardless of whether they are growing
boutique, small-batch artisan cannabis,
or large-batch, low-cost flowers. A
crop’s output largely dictates the cost to
grow it, which is to say that a large yield
typically trumps the other variables
within a cost of goods analysis. One
would use this data analysis process to
determine, for example, if a particular
costly supplement is worth it, or what
the return on investment might be on a
state-of-the-art lighting technology, or
whether a particular genotype (clone)
might be suitable for increased production
in the garden.
For years cannabis cultivators would
speak of their yields in terms of how
many pounds or kilos they produced
of dried, processed flowers per 1,000-W
flowering light. A good crop might have
led the happy gardener to say, “I got
two pounds per light!” Although this
method of measuring a batch’s (or crop’s)
result does give some indication of what
was achieved, it does not account for
the wide window of different genetics’
flowering times. While the right cut of
Sweet Tooth No. 3 might finish in 42 days
of flowering, a Super Silver Haze may
take as long as 84 days, doubling the
flowering time, thus it would have to
yield double the dried grams per crop as
the Sweet Tooth to yield the same when
accounting for the time that the space
was used to grow the batch.
In order to account for both the flowering
time and the weight yielded from a
particular batch, I developed a simple
and useful system of data analysis of
true yield results and trends. First, the
number of 1,000-W lights used in the
batch is determined. Then the total
grams of dried manicured flowers and
the days of flowering time are assessed.
The equation is as follows: Yield in
grams ÷ number of lights ÷ days in
flower = GPD average.
Here’s an example: 1,000 grams yielded
÷ 1 light ÷ 70 days in flower = 14.29. So
this single light’s crop had a gram per
day (GPD) average of 14.29. No matter
how large or small a crop is, it can be
measured as such, allowing an equal
playing field of crop analysis irrespective
of crop size or time it takes to flower
particular genotypes. Here’s another example
from a larger batch: 58,453 grams
yielded ÷ 75 lights ÷ 67 days in flower =
equals 11.63 grams per day.
Upon examination, most batches
yield between six and 16 grams per
day. Anything below is essentially crop
failure, anything above is phenomenal.
I consider any garden operating at 10 or
above acceptable, with 12 as a target.
“A crop’s output
largely dictates the
cost to grow it, which
is to say that a
LARGE YIELD typically
trumps the other
variables within a cost
of goods analysis.“
At that point there is potential to
increase yield through tweaks to the
environment, nutrient regimens and
genotype (strain or cutting) selection.
The GPD model can be used to
assess anything from the yields
of a specific time period from a
specific section of the garden, to
an individual gardener’s effectiveness,
or to assess the profitability
of different genotypes from a batch
of seeds. It can be used to compare
facilities, to finely adjust strainspecific
nutrient regimens, or even
to determine the ideal temperature
and humidity levels for different
genetics. As the long as the data
gathered is accurate, it can be the
best tool to maximize a garden’s
performance, which is the ultimate
engine of profitability.
The GPD yield analysis model is
the most effective method to monitor
yield trends in your garden, whether
you operate with a single light in a
closet or manage a million watts.
GDP provides clarity to the decisions
that impact the bottom line on a
daily basis. As the cultivation industry
becomes more sophisticated, high
level operators will need to use tools
like the GPD yield analysis model to
inform critical decisions.
Ben Burkhardt entered the adolescent
medical marijuana industry in 1998
in San Francisco and then Los
Angeles. He then relocated to Denver,
where he owned and operated
the largest indoor grow facility in
the country, an infused products
division and more than a dozen retail
locations. He is now pursuing national
and international opportunities with
his company Sunlight Green Systems.
14
grow. heal. live. enjoy.
myhydrolife.ca