let there be light reflection
air or water to remove a good portion of the heat created by
HID bulbs as they emit light. The biggest advantage of these
reflectors from a light energy standpoint is that they allow
the grower to get the light source closer to the plant canopy
without creating stress. Some growers report yield increases of
close to 10% by using an air- or water-cooled reflector. Many
“just 15 years ago, it was common
for many growers to hang
in their growrooms.”
bulbs
bare
growers will also use reflective films or reflective paint on
the walls of their growrooms to reflect light back toward the
plants. Both light reflectors and reflective films can be made
from a variety of reflective materials.
Flat white paint or flat white sheet metal are decent reflective surfaces. In fact, a flat white color has a reflective rating
of around 85%. Mylar-type surfaces give a slightly higher
reflective rating (just over 90%) and are commonly used
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Maximum Yield USA | January 2015
by growers to create a reflective room. Many reflectors use
a pebbletone aluminum, which provides more than 90%
reflectivity and effectively diffuses the light. The best reflector would actually be a mirror with a 100% reflectivity rating.
However, mirrors are not the best choice for horticulturists
because they do not diffuse the light in any way. In fact, if
used in a light reflector, mirrors may be somewhat counterproductive because they could create additional hot spots.
Light Reflector Cross-patterns
When two or more light reflectors are placed in an indoor
growroom and their light footprints (area of light th