Maximum Yield Modern Growing | Canadian Edition | May June 2017

tapped in
ask the experts
Q
Hi,
What are the commercial options for mediums and lights (HPS or LED)? I have 17,000 square feet.
Do I need 300 lights or more? Also, how should I set up the clone/mother room? Should I have
trays or just pots, no trays? I’m looking to veg in three weeks, ideally, or four weeks, max.
– Paul
Paul,
Thank you for your questions.
A
First, when setting up a
commercial growing facility,
remember that automation
is your best friend. The more
equipment in the garden that
can be automated, the better.
This automation will, in turn,
reduce the amount of work
that you must do.
In many ways, the choice of
medium and growing system
comes down to the grower’s
personal preference. Just about
any growing medium can be
used successfully. However,
when gardening on a large
scale, logistics—including
disposal of the medium—should
be considered. Stone wool is
lightweight and easy to transport,
making it a good choice for largescale
gardens. It is also a great
medium for top feed systems,
which are the preferred system
for growers with commercialsized
operations. Top feed
systems with trays or troughs are
easiest to automate on a large
scale. Still, while stone wool is
commonly used by large-scale
commercial growers using this
type of system, any soilless
medium can be used just as
effectively with a top feed set-up.
The simplest way to determine
the horticultural lighting
requirements for a commercial
garden is to think in terms of
watts (W) per square foot of space.
The typical high-performance
indoor garden will provide 40-50W
of artificial light per square foot
of garden space. It is important
to remember that we are talking
about actual garden space,
not the total square footage
of the room. Assuming your
17,000-square-foot facility will be
filled wall-to-wall with plants,
you should plan on providing
a minimum of 680,000W of light
(for example, you could use 680
1,000W HID lighting systems).
You could possibly reduce the
total wattage required if you are
using induction or LED lighting
systems in place of HID lighting
systems. Induction lighting
systems and LED are more
efficient at converting electricity
into photosynthetically active
radiation (PAR), which means
they can provide the same usable
energy as other technologies
while consuming less electricity.
That being said, intensity is
crucial to the development of
large fruits or flowers, which is
why HIDs still remain the most
popular choice for large-scale
commercial gardens.
How long the plants are kept
in the vegetative stage depends
completely on how large you
want them before initiating
the flowering cycle. For most
indoor growers, the desired
size can be achieved in three
to four weeks of vegetative
growth. For the cloning stage,
again, automation will be a
big factor in reducing labour
and increasing efficiency.
A dedicated cloning space
complete with temperature,
humidity, watering, and
lighting automation will go
a long way in making the
transitions of a perpetual
garden smooth. The mother
plant(s), however, are typically
kept in a soil container and in a
separate area or room.
Keep on Growing,
Eric Hopper
Eric Hopper’s past experiences within the indoor
gardening industry include being a hydroponic retail
store manager and owner. Currently, he works as a
writer, consultant, and product tester for various indoor
horticulture companies. His inquisitive nature keeps him
busy seeking new technologies and methods that could
help maximize a garden’s performance.
PAR
Photosynthetically active radiation (PAR) is the amount of light available for photosynthesis. This light (light in
the 400-700 nanometer wavelength range) is required for all plant growth. Higher PAR promotes better plant
growth, and monitoring PAR is important to ensure plants are receiving adequate light for this process.
– fondriest.com
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