Professional Marijuana Grower November-December 2018 Issue | Page 28

simply dropped into existing greenhouses.
There are two serious shortcomings with
this option. First, they tend not to provide
complete darkness and without proper light
deprivation, cannabis plants cannot ade-
quately flower. Second, turnkey blackout
systems tend to break down over time and
fail growers looking for a system that is a
long term solution. What a business owner
initially saves in purchase price, they will
certainly make up for in repairs or replace-
ment.
Universal blackout systems that are dropped
into a greenhouse can create a couple
environmental control issues. Because these
systems are not designed to work within
a specific greenhouse layout, they can
develop stress points with repeated use.
It’s not uncommon for blackout curtains to
drag against heating units or other tools
and accessories every time the curtains are
opened and closed. This constant wear
and tear eventually takes its toll, forcing
growers to make time-consuming repairs or
buy replacements. Mass produced blackout
systems also run the risk of completely block-
ing vents or exhaust fans, forcing growers
to reconfigure their setup or get rid of the
blackout system and start all over again.
Each time engineered blackout curtains are
deployed, growers can rest assured they
will last for many years and remain in ideal
condition. When each piece of greenhouse
equipment has already been accounted for,
there is no risk of the light deprivation sys-
tem dragging against greenhouse compo-
nents or accessories.
Light deprivation designers often see grow-
ers forget how a blackout system will affect
the interior greenhouse climate. Blackout
curtain systems can prevent interior green-
house heat from reaching the outer structure
walls, so growers should be prepared to
have a snow melting program built into their
roof, if that is prescribed in their building
code.
Equally important is that growers in warm-
er climates should have active ventilation
in place when the curtains are closed.
HAF fans, exhaust fans and shutters with
breathable walls work best. Do not rely on
ridge vents to do the work of ventilation, as
they will not work when a blackout system
28 • Professional Marijuana Grower
November/December 2018