ASK THE EXPERTS
Q
I’m about to buy my first grow tent.
What sort of lighting system is best?
And how many lights do I actually need?
Cheers, Nigel
High intensity discharge lights, including
metal halide and high pressure sodium,
are still the most commonly used lighting systems in grow tents. However, many
growers have been turning to fluorescents
or LEDs with great success. Although grow
tents differ from a typical growroom in
a few ways, the same basic principles for lighting requirements still apply. If you are using HID or fluorescents, you
should provide around 40 W of lighting per square foot of
garden space. For example, let’s say the grow tent has a 4- by
4-ft. floor space that will be filled with plants. This equates
to a 16-sq.-ft. growing area. For this size, you could use a
600-W light to provide 37.5 W per square foot. If cooling
the grow tent is not an issue, you could opt for a 1,000-W
system, which would provide 62.5 W per square foot. Yet
another option would be using two 400-W lighting systems
for a total of 800 W, or 50 W per square foot. For increasing
growth rates and yields, more light energy is always better,
but higher-wattage systems enclosed in a grow tent can cause
serious heat issues. This is the reason why many people are
turning to LEDs, which generally operate at cooler temperatures than HIDs or fluorescents. Just be sure to closely compare LED lighting systems before making a final decision,
and find a system that produces an equivalent PAR output
to that of a 600-W or 1,000-W HID lighting system. The LED
system that produces the most PAR per watt consumed will
be the most efficient choice
For first-time grow tent users, a 3- by 3-ft.
or 4- by 4-ft. tent is a good choice and can
accommodate up to eight plants. The type
of lighting you choose depends on what
you are growing. If you are only using the
tent for vegetative growth, a 2- or 4-ft.,
8-bulb T5 fluorescent light fixture will
properly illuminate the area. If you are growing plants all the
way to the flowering or fruiting phase, a 400- or 600-W high
pressure sodium or metal halide light fixture will properly
cover the area. When upgrading to larger grow tents, keep
in mind that one HPS or MH should cover about 4-6 plants.
If you are using a 1,000-W light bulb, it is wise to use a dimmable ballast to give you the option of running a higher or
lower wattage. LED (light-emitting diode) and LEC (lightemitting ceramic) lights are also good options. These lights
come in a variety of sizes and spectrums, so be sure to consult
the manufacturer regarding how much area is covered by
each fixture. One important thing to keep in mind is that
temperatures in this type of controlled environment can
easily and drastically increase, depending on the light source,
so proper cooling and ventilation is a must to help ensure
optimal plant growth and results.
Keep on growing,
Eric Hopper
Good luck,
Kyle L. Ldenburger
Eric Hopper’s past experience within the
indoor gardening industry includes 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.
24
Maximum Yield USA | November 2015
Kyle L. Ladenburger is a passionate indoor
and outdoor gardener. He is also a freelance
garden writer. With more than 10 years’ experience
in the industry working for Age Old Organics, he
is well-versed in numerous growing methods with
a focus on soil health.