MJBiz - August 2023 - 28

applied
Science
increases yields and promotes a richer
cannabinoid and terpene profile.
Heat and Humidity
Temperature and humidity levels also
can be lowered as harvest approaches,
with the aim of beginning to dry out
the plants. Less moisture preserves
terpenes and protects against microbial
contamination, which is more common
late in the flowering phase, when
plants are big and near full maturity.
Lowering temperatures inside a
grow room toward the end of the
flowering phase can benefit flower
quality because it mimics the cooler
temperatures of fall.
" It helps those buds tighten up a little
bit. They start to notice it's getting cold,
so they start to tighten up. They get a
little bit harder, they get a little denser-
and that's obviously what we're looking
for in our final product, " Robertson said.
He warned, however, that " when you
get too cold in a room, the dew point
is going to promote a certain type of
moisture in the air that promotes mold
and pathogenic growth. "
Toward the end of the flowering
phase and shortly before harvest,
Robertson said he likes to maintain
temperatures around 72 degrees; he
also dials humidity back to 40%-45%.
Marco Malatrasi, director of
production at Fluent Cannabis, which
operates in Florida, Pennsylvania and
Texas, also lowers his temperatures
from the high 70s during the first several
weeks of the flowering phase to the low
70s for the last few weeks of flowering.
" Most varieties will show a sensitivity
to cold, and they'll produce more
anthocyanins, " Malatrasi said, referring
to the purple and red pigments that
appear on some cannabis strains.
Jushi, which maintains a
temperature range of 78-82 degrees
during the first several weeks of
flowering, drops the temperature to
68-70 degrees near the end of the cycle,
late in week seven or week eight.
" Lower temperature/lower humidity
28 August 2023 | MJBizMagazine
Cultivation staff at Jushi drop indoor grow room temperatures by 8-10 degrees around
week eight of the growing cycle. Contributed photo
are keeping microbials low, " Malman
said, " And we're not volatizing terpenes
with high temperatures near the end. "
Lowering humidity near the end of
the flowering phase also helps reduce
moisture in the flower as harvest nears,
said Frank Golfieri, the Massachusettsbased
director of cultivation for
multistate cannabis operator Insa.
Golfieri likes to gradually reduce
temperatures to about 60 degrees and
50% humidity by harvest. Depending
on the strain, he could start reducing
temperature and humidity a few days
or a couple of weeks before harvest.
Nutrients
Another important change that
cultivators make as harvest nears is
their use of nutrients.
" Harvest is an important time
to cut back on certain nutritional
inputs and maybe increase others, "
Robertson said. " Hands down, the
most important nutritional input that
will direct how the plant is growing
at any stage is going to be nitrogen. If
we don't start to lower our nitrogen,
that plant is going to hormonally
think at some point that it still wants
to produce some sort of vegetative
growth, meaning it will expand in
size or wants to put more work into its
family's production. "
Growers at 4Front typically start
reducing nitrogen inputs about
halfway through the flowering cycle " in
anticipation of harvest, to make sure
MJBiz - August 2023

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