Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible

filament, a super fine wire inside the bulb. The filament resists the flow of electricity, heating it to incandescence, causing it to glow and emit light. The incandescent bulbs work on ordinary home current and require no ballast. They come in a wide range of wattages and constructions.
    Most incandescent lamps have a spectrum in the far-red end, but there are some incandescent grow lamps that have an enhanced blue spectrum. They are expensive to operate and produce few lumens-per-watt. They are most efficiently used as a source of rooting medium heat for clones rooting under cool fluorescents.
Tungsten Halogen Lamps
    The tungsten halogen lamp is a poor grow light. It was originally called Iodine Quartz lamp. The outer tube is made of heat-resistant quartz. The main gas inside the quartz tube was iodine, one of the five halogens. Today, Bromine is used most often in the lamps. Similar to incandescent lamps, they use a tungsten wire filament and a sealed bulb and are very expensive to operate. Their lumens-per-watt output is very low. They run on a household current and require no ballast. Tungsten bulbs are as inefficient to operate as are the incandescent lamps. Their color spectrum is in the far-red end with 10-15 percent in the visible spectrum.

CFL light spectrums are perfect for growing plants, even cannabis!
LP Sodium Lamps
    Low Pressure (LP) sodium lamps are monochromatic. Do not use these lamps to grow cannabis. They produce light in a very narrow portion of the spectrum, at 589 nanometers, and emit a yellow glow. They are available in wattages from 55 to 180. Their lumens-per-watt conversion is the highest of all lamps on the market today. Their main use in industry has been for security or warehouse light.
    Lamps require specific ballasts and fixtures according to wattage. The fixture for a 180-watt lamp is just a little larger than a fixture for two 40-watt, four-foot (120 cm) fluorescent tubes.
    After visiting hundreds and hundreds of grow rooms over the last 20 years, I have seen only one LP sodium lamp in use.

Electricity & Safety
    You don’t need to understand the basics of electricity to grow indoors or in a greenhouse, but understanding the basics will save you money, time, and possibly the shock of your life.
    Before you touch anything electrical, please remember to work backwards when installing electrical components or doing wiring. Start at the bulb, and work towards the plug-in. Always plug in the cord last!
    Ampere (amp): is the measure of electricity in motion. Electricity can be looked at in absolute terms of measurement just as water can. A gallon is an absolute measure of a portion of water; acoulomb is an absolute measure of a portion of electricity. Water in motion is measured in gallons per second, and electricity in motion is measured in coulombs per second. When an electrical current flows at one coulomb per second, we say it has one ampere.
    Breaker Switch: ON/OFF safety switch that will turn the electricity OFF when the circuit is overloaded. Look for breaker switches in the breaker panel or breaker box.
    Circuit: the circular path that electricity travels. If this path is interrupted, the power will go off. If this circuit is given a chance, it will travel a circular route through your body!
    Conductor: something that is able to carry electricity easily. Copper, steel, water, and your body are good electrical conductors.
    Fuse: Electrical safety device consisting of a fusible metal that melts and interrupts the circuit when overloaded. Never replace fuses with pennies or aluminum foil! They will not melt and interrupt the circuit when overloaded. This is an easy way to start a fire.
    Ground: means to connect electricity to the ground or earth for safety. If a circuit is properly grounded and the electricity travels somewhere it is not supposed to, it will go via the ground wire into the ground (earth) and be rendered harmless. Electricity will travel the path of least resistance. This path must be along the ground wire.
    The ground is formed by a wire (usually green, brown, or bare copper) that runs parallel to the circuit and is attached to a metal ground stake. Metal water and sewer pipes also serve as excellent conductors for the ground. Water pipes conduct electricity well and are all in good contact with the ground. The entire system, pipes, copper wire, and metal ground stake conduct any misplaced electricity safely into the ground.
     
----
Overload Chart

    Connect only