127 lines
6.2 KiB
Plaintext
127 lines
6.2 KiB
Plaintext
Message-ID: <081307Z16051994@anon.penet.fi>
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Newsgroups: alt.drugs
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From: an94721@anon.penet.fi
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Date: Mon, 16 May 1994 08:07:47 UTC
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Subject: GROW LIGHTS FAQ
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GROW LIGHTS FAQ (Last update, May 15th, 1994)
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The purpose of this FAQ is to help limit the spread of misinformation
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regarding effective artificial lighting systems, and help those who
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choose to grow plants under artificial lighting make an informed
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decision before buying a lamp.
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Most of the information contained in this FAQ comes from printed
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sources, and some from electronically distributed files. Very little
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comes from my own experience, as I have not owned, used or examined
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most of the systems discussed here.
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This FAQ is not going to tell you how to use your lamp, that
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information can be found in most grower's guides.
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Introduction:
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There are three major types of lighting systems available right now:
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incandescent, fluorescent, and high intensity discharge. Incandescent
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lights are horribly inefficient (especially the screw-in "grow bulb"
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type) and really not an acceptable option for plant growth. Although
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they are inexpensive to purchase, their cost of operation makes them
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the costliest source of light.
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Flurescents:
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Until the early 1980's most indoor growers used fluorescent lights to
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illuminate their garden. These tubes have tremendous advantages over
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incandescents. They emit about 3 times as much light as an
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incandescent (given the same wattage), and the light spectrum is one
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that plants con use more effectively.
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However, they do certainly have their limitations. Light is emitted
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over a large area, so it is not concentrated. Because of this, the
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lights have to be hung very close to the plants, and constantly moved
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to accommodate plant growth. This makes garden maintenance rather
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difficult.
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Florescents are, however, very useful in cloning, and starting
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seedlings. Because in these stages, a plant is not growing vertically
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very quickly, the disadvantages of moving the lights are reduced. They
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also put out a more gentle light than the HID lamps, and release less
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heat.
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If you choose to use fluorescents, it is best to purchase the 'cool
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white' variety. The ones that are sold as grow lamps (including
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grow-lux, vitalite, etc.) are much less efficient than a standard
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fluorescent, and just do not put out enough light to be useful. The
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slightly different spectrum produced by these lamps does nothing for
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most plants.
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High Intensity Discharge Lamps (HID's)
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High intensity discharge lamps are easier to use, and more
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efficient. Low wattage HIDs are sometimes sold for household outdoor
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use. Large Wattage lamps are used for lighting streets, parking lots,
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stadiums and other large areas. They come in two basic flavors:
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METAL HALIDES or MH lamps emit a white light that looks slightly
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bluish. They are used to light stadiums, convention centers,
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gymnasiums, and other large areas where a natural looking light is
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desired.
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HIGH PRESSURE SODIUM or HPS lamps emit a pink or amber light. They
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are used for lighting parking lots and other areas where the color
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of the light is not important. HPS units are much more efficient
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than MH ones, producing more light and less heat per watt of energy
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consumed. They are often used alone with no detrimental effect on
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the plants, and will promote faster plant growth than MH lamps
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during both vegetative growth and flowering. Combinations of
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bulbs are _NOT_ required, as the HPS lamp does produce all of the
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light spectrums necessary for healthy growth.
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MH lamps are available in 175,200, 400 and 1000 watt sizes. HPS
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lamps come in 50, 75, 150, 400 and 1000 watt sizes. Each lamp
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requires its own ballast, which comes with the fixtures that are
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designed to use these lamps, and are also available separately.
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The following chart shows how much light each lamp emits, and the area
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that it covers adequately:
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Lamp # of Lumens Sq. Ft
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---- ----------- ------
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4'FL (CoolWhite-40W) 2,960 1-2
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8'FL (CoolWhite-75W) 5,800 2-4
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MH 175W 14,000 5-10
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MH 400W 40,000 12-20
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HPS 70W 7,600 3-6
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HPS 150W 16,000 6-11
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HPS 400W 50,000 15-30
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Gardens should receive 1000-3000 lumens per square foot. Successful
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gardens usually are lit at around 2,000 lumens per square foot. During
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the vegetative stage, plants stretch out when they receive low levels
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of light. During flowering, the flowers are looser and sparse.
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So what is the best lamp for growing? It depends on your budget. HPS
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lamps are by far the best overall, but they are also the most costly to
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purchase and setup (although some less honest growers have a tendency
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to steal them from college campuses and the like). However, they are
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the cheapest to operate, and the utility savings does eventually add
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up.
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A quick warning: At least in the US, there are large government
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agencies whose only purpose is to eliminate the growth of marijuana.
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Although purchasing a high powered lighting system does not mean that
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you will be growing pot (and many people grow other things
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artificially), it is still not a really good idea to link your name
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with the purchase of one of these lamps (especially the larger ones).
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Go into the store knowing exactly what you want, pay for it in cash,
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and do not give them your name (or give them a false one if they even
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ask). Most lighting distributors will not ask any questions.
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I wish you a healthy and happy crop.
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