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Hydroponic Lamps

Lighting Systems: Use And Identification

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Fluorescent

Before high intensity discharge light came along, indoor growers depended mainly on fluorescent lights for best results. They are inexpensive, reasonably energy efficient, and most emit a wide enough spectrum of light for plant growth. There is a wide range of fluorescent bulbs or "tubes" available, and are categorized by wattage, length, and colour of spectrum range. Indoor growers should look for the type specifically made for plants such as the vita-Lite* or Ultralume 5000*.

The fixtures for these lamps are usually complete with lamp holders, reflector, and built-in ballast. Since the introduction of H.I.D. lights, fluorescent now are mainly used for propagation and early vegetative growth. The 20 watt,24 INCH, and 40 watt, 48 inch, are the most common. The more intense and energy efficient H.I.D.'s are now the choice for maturing high-light plants and vegetables indoors.

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High Intensity Discharge (H.I.D.) Grow Lights

Metal halide lights were created to provide a spectrum as close as possible to that of the natural sunlight. This coupled with their intensity and energy efficiency, makes them ideal for indoor gardening. The bulbs range in size from 100 watt to 1000 watt with 400 watt and 1000 watt most popular.

Read about Homegrown's line of SunMaster Metal Halide Grow Lamps.

An abundance of blue light emitted by metal halide makes them the best light for propagation and vegetative growth, promoting short internodal length High Pressure Sodium lights do not emit as broad a spectrum as Metal Halides lights, but have many advantages, especially when used in conjunction with halide. Sodiums last longer, and burn brighter, but are still more energy efficient.

More yellow/red colour in the spectrum and less blue promotes a higher flower-to-leaf ratio in flowering plants. H.P.S. lights are widely used in commercial greenhouses, where natural sunlight provides sufficient blue. A combination of the two lights provides the best balanced for indoor growroom, especially when used with a light mover. 430 Watt Son Agro H.P.S. bulbs which supply 30 extra watts than regular ones are now available. This extra light in the blue end of the spectrum is great news for indoor growers. If you are planing a "single lamp" growroom, you can still get the benefits of both halide and sodium light. High pressure sodium "conversion bulbs", specially made to operate with M.H. ballasts, are available in 400 watt and 1000 watt models. The bulbs can easily be interchanged as needed, using the same ballast and fixture. The size of the light you will need will depend on the size of the growing area, and the type of plants you wish to grow.

High-light plants such as herbs and vegetables will require between 20 and 60 watts of light per square foot of growing space. A 400 watt metal halide in a three foot by three foot area will provide 45 watts per square foot, compared to 25 watts per square foot in five foot by five foot growroom. A 1000 watt metal halide in a five foot by five foot area will provide 40 watts per sq.ft., compared to 20 watts per square foot in a seven by seven foot growroom.

Proper reflectors, light movers, and reflective material on walls greatly increases intensity and efficiency of these lights.

Most high intensity lights can be run with either 120 volt (standard house current), or 240 volt (e.g. used for electric dryer).
Electricity cost would be the same but the latter would draw half the amps allowing the grower to run twice as many lamps on the same electrical circuit.

Light timers are available for either voltage but always check to see that the amperage rating on the timer exceeds that of the light or lights.

Care should always be taken when installing and using H.I.D. lights. Remote ballasts should be placed safely out of the way where they can't be knocked over or splashed with water. Never keep your ballast on the floor in case it gets wet. Installing the fixture and reflector is simple. Locate a stud in the ceiling near the centre of the grow area. Screw a metal hook capable of holding 40 to 50 pounds into the stud and test it's strength. Attach a 4' to 6' length of lightweight link chain to the hook or hooks on top of the fixture and hang the fixture from the ceiling hook at the desired height. The link chain allows you to easily raise and lower the light when necessary. Hold the lamp near the base and firmly, but gently, screw the bulb into the socket. Connect the timer to the power source, plug the power cord from the ballast into the timer which should be set in the "on" position. It may take up to 30 seconds for the bulb to ignite and up to five minutes to reach full brightness. As the lamp ignite, they tend to flicker and change colour for several minutes. This is quite normal, especially with halide bulbs, which may appear to change colour slightly during normal use. If the lamp does not ignite after 30 or 40 seconds, unplug it. After the power has been disconnected, check

  • that the bulb is screwed in all the way
  • that the timer is set on the "on" position
  • that all plugs or electrical connections are O.K.

NOTE: Do Not Open The Ballast Enclosure To Check Wiring Yourself! H.I.D. capacitors can hold a charge even after the ballast is unplugged! Once these points have been checked, try the light again.

Once a metal halide lamp is turned off it requires a 15 to 20 minute "cool down" period before it can be re-started. If ample cooling time is not allowed, a "hot start" occurs, and too many "hot starts" can seriously affect the intensity and longevity of the bulb. For best results, replace halide bulbs after one year of steady use. High pressure sodium lamps require only 2 to 3 minute "cool down" period and need only be replaced every two to three years.

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Lighting Tips

  • mylar reflects with up to 95% efficiency
  • flat white paint reflects with up to 80% efficiency
  • never use tinfoil for reflection it creates "hot Spots"
  • use air cooled reflectors when heat build-up is a problem
  • 15 minute time delays for halides prevent "hot starts"
  • low pressure sodium lights greatly increase intensity for pennies a day
  • light movers increase growth by up to 40%
  • halide "super"bulbs increase intensity but not your hydro bill
  • 430 watt Son Agro sodiums supply 30 extra watts of blue light
  • wear sunglasses when working close to an H.I.D. bulb
  • if your light fails, don't try to fix it yourself, contact a qualified expert
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