Aeroponics
Lights and Timers
Lighting will be one of your most important decisions
in setting up your grow room.
First, look at your room. Metal halide or High Pressure
Sodium lamps emit a considerable amount of heat. Do you have enough
ceiling height to raise your lamps 18 inches above your plants AT
HARVEST TIME? The use of remote ballasts and ventilated hoods with
travelers will increase headroom and allow closer placement of lamps
to plants.
If you have very little headroom consider a SunBlaze
T-5 fluorescent lamp. It is only about 2 inches thick, emits very
little heat, and produces more lumens than a 400 watt metal halide.
This lamp can be placed as low as a few inches from the plant canopy.
This is a real advancement in fluorescent lighting.
How much light do you need? A 1000W metal halide
will provide plenty of light for a 8' x 8' room. You will get better
light "coverage" by using a light traveler or setting
two lamps a few feet apart and using timers to alternate the lamps
during the light cycle.
During the light cycle (the period the lights are
on) you want the best coverage you can get. If you have one lamp
centered over your crop the outside of the perimeter will not receive
the same intensity as those plants directly under the lamp. You
can compensate for that by putting your light on a "traveler"
which will physically move the lamp over the plants or you can improve
your "coverage" by adding lamps. If you add one lamp you
have doubled your energy consumption.
An alternative to doubling your energy consumption
by running two lamps or putting one lamp on a traveler is to mount
two lamps stationary. Have one come on for 6 1/2 hours
and have the second lamp come on a half hour before the first goes
off, and run it for 6 1/2 hours. You will get incredible coverage
with the energy consumption of one lamp run for 13 hours. The overlap
is to prevent even a short dark cycle between the two lamps firing.
In nature plants "follow" the sun, and get wider "coverage"
due to the suns "movement". To carry things out to even
a higher degree, place a high pressure sodium lamp between the two
metal halides, run it for only 4 hours per cycle during the middle
of the light cycle. You have given your plants a home run with only
17 total lamp hours per day.
Be sure to use timers which are rated for the amperage
of your lamp and designed for inductive uses. Typically this type
of timer will be called an appliance or equipment timer.
Metal halide lamps with "warm" bulbs have
pleased many a grower from seedling through the blooming phase.
If finances aren't a limiting factor mix metal halide and high pressure
sodium. For a small to medium size setup a 400w lamp will suffice.
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