FEATURESTORY
by Eric Hopper
Maximizing Lighting Efficiency
O
f the many variables which affect plant
growth in an indoor garden or green-
house, none are as influential as the ar-
tificial light source. The artificial lighting
system is literally the sole energy source for an indoor
garden and without light energy photosynthesis is
impossible. It is important for horticulturists to re-
member that each indoor garden has a limited amount
of light energy. To maximize his or her return on in-
vestment and to make an indoor garden as efficient as
possible, an indoor horticulturist must make the most
of his or her given light energy.
When I was a hydroponic retail store manager,
growers constantly asked me how they could increase
their yields. My answer was always “maximize the effi-
ciency of your light source”. In other words, to get the
most out of an indoor garden, a grower must know
the basics of light energy, how it relates to indoor hor-
ticulture, and how to maximize its efficiency.
Light Energy
The inverse square law states that light energy
diminishes exponentially as it travels away from its
source. Light energy is emitted evenly and in all direc-
tions from one point. As the light travels and spreads,
the intensity diminishes. The most important detail for
indoor growers to remember is that light intensity is
directly related to the distance from the light source.
Plants grown outdoors under the sun are seemingly
unaffected by this phenomenon because, after travel-
ing all the way from the sun to the earth, the distance
from the top of the plant to the bottom is quite insig-
nificant.
Plants grown indoors, however, are extremely
susceptible to the inverse square law because the
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www.GardenandGreenhouse.net
October 2017