Combining Sunlight & Grow Lights:
Supplemental
Greenhouse Lighting
by Kent Gruetzmacher
Indoor and outdoor growing are no
longer distinct schools of thought.
Greenhouse cultivators have
combined the practices to create
a new, more cost-effective method
that uses both sunlight and grow
lights to power crop production.
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Maximum Yield
O
nce considered two distinct schools of thought in
horticulture, the line between indoor and outdoor
cultivation is being blurred. Highly sophisticated,
year-round greenhouses are at the forefront of this
fusion movement as they utilize the best practices of
both methodologies in a creative give and take. These
operations utilize the sun’s energy to power essential
plant functions while implementing indoor growing
technologies like light sensors, blackout tarp systems,
dehumidifiers, and industrial heaters to mimic indoor
environmental controls in outdoor settings.
Perhaps the most vital technological application
in these modern-day greenhouses is that of
supplemental lighting. In indoor gardening, lighting
is one of the most important factors dictating the
outcome of a harvest. However, it is also one of the
costliest elements of an operation, with an overhead
of at least $400 per unit for 1,000W double-ended high
pressure sodium (HPS) lights and $800 per unit for
comparable light emitting diodes (LEDs). Taken to
a commercial scale, this overhead can prove quite
intimidating as it is solely up to these artificial
light sources to feed every square inch of a massive
garden canopy. Then there is the astronomical cost of
running the lights in these large-scale set-ups. Some
10,000-square-foot warehouse grows have reported
power bills to the tune of $12,000 monthly.