32 MAY/JUNE 2017 LEDSMAGAZINE.COM
life science | HORTICULTURAL LIGHTING
The Earth’s population is projected to reach 10 billion by 2050, and there are growing concerns about water,
energy, and food availability for such a high
number of people. To maintain our current
water supply and produce enough food to
feed our fellow human residents, several different practices must be adopted within the
agricultural sector. One potential solution to
the problem is growing vegetables in water
through hydroponics, aquaponics, or aeroponics. LED-based horticultural lighting
works as an excellent companion technology to enhance crop production for indoor
applications, especially in warehouses — in
what is known as vertical or urban farming
— versus greenhouses.
The three water systems are soil-less
methods of agriculture that can produce
5× the amount of food in the same space as
typical outdoor agricultural methods. Furthermore, these practices utilize at least
90% less water than the irrigation practices
used in outdoor agriculture. With food and
water availability possibly being the greatest future challenge facing humankind,
these systems will provide significant relief
to those concerns.
One common question with such agri-
cultural systems is how the yields compare
to soil-grown harvests. As stated earlier,
these systems provide the ability to grow
roughly 5× the amount of food in the same
space compared to outdoor agriculture. The
ability to stack the water and lighting sys-
tems in shelves allows for a condensed and
efficient use of space. Along with that, uti-
lizing LED grow lights designed to deliver
appropriate light spectra for each crop, pro-
vides more photosynthetic active radiation
(PAR) than what most plants receive from
the sun (Fig. 1). For instance, Mount Ver-
non, which is one of the most notable farm
towns in Iowa, receives a maximum of about
14 hours of photosynthetic light a day in the
summer, but in the winter it can drop to as
low as eight hours of light. When equipped
with horticultural solid-state lighting (SSL),
plants reach their maximum photosynthetic
potential every day. Growers just need to be
careful about giving their crop too much of
the heat energy that comes with the any light
source. Therefore, periods of no light expo-
sure must be set aside each day for plants.
The reduced heat and the lower electricity
operating costs of LEDs have opened a whole
new chapter in agriculture.
Reaping the economic benefits
With greater yields than the common out-
door methods of agriculture, the next con-
cern is whether these horticultural systems
are economically efficient. The quick answer
is “yes” — with an asterisk — based on three
key factors: type of plant; sales region; and
cost of electricity
People outside of the agriculture industry
might assume that cannabis, with medical
and recreational marijuana, is the only “cash
crop.” Since cannabis takes multiple months
to grow and grows multiple feet tall prior to
harvest, it uses up more real estate — horizontally and vertically — than other crops
like lettuce and micro-greens. Indoor farmers can “rack and stack” leafy greens four
or five high and turn the crops more than
once a month. California lettuce is shipped
Buyers benefit from LED grow light guidance
With LED-based horticultural lighting on the rise, specifiers and end users need education to select
the optimal fixtures for projects. RYAN MITCHELL and CHARLIE SZORADI deliver a guide to navigating
spec sheets and performance calculations for best results.
RYAN MITCHELL is account manager
and CHARLIE SZORADI is chairman
and CEO at Independence LED Lighting
( independenceled.com).
FIG. 1. Sample linear LED grow light modules with different color diodes on each module.