In general, there are four types of lights that are suitable for growing plant life:
Compact Flourescent Lighting (CFL) Known as Compact Flourescent Lighting or its common counterpart T5, this is considered the cheapest suitable lighting for an indoor grow. Typically fitting into an E26/E27 socket, CFL lightning can be nice for small form factor grows, such as space buckets or very small closets. By and large, they are still considered to be the least effective lighting for growing. CFL's can be found in a range of lower wattage bulbs and fixtures. T5 lighting is an extremely common form of flourescent lighting and is used by many growers in the seedling/vegetative stage of growth. They are considered to be relatively small initial cost and a low cost to run.
High Intensity Discharge Lamps (HID) Known as High Intensity Discharge lamps, HID lights are considered to be the most common form of lighting for growing indoors. The technology behind HID bulbs and fixtures is tried and true and has been used in commercial and home grows since its adoption in the 1970's. Generally HID fixtures work by having three components:
- Hood - Three types of common hoods, Cooled Tube, Open Wing Hood, and Air Cooled
- Bulb - HPS or MH, MH lights are typically used for vegetative state and HPS lights are used for the flowering stage, however HPS can be used as a full cycle lighting solution
There are two types of Bulbs that see general use in HID grow settings, High Pressure Sodium (HPS) and Metal Halide (MH). HID lighting gives off more heat and takes more electricity than its CFL and LED counterparts, however, in recent years, it has become one of the cheaper options for a strong grow light with good LED's a being significantly more expensive option.
Light Emitting Diode (LED) The newest type of grow lighting, LED lights are quickly becoming one of the most popular lighting technologies for indoor gardening. In prior years, LED fixtures were considered very cost prohibitive and the results were worse than their HID counterparts. However as research and development into LED tech has become much more common, the price has come down considerably. In general, I would consider LED's to have three "types" of lights today, being:
- Quantum Board
Ceramic Metal Halide (CMH) Known as Ceramic Metal Halide, these lights are very similar to a typical HID light. However they are more efficient and have the best spectrum of any "HID" type lamp. Additionally they have a longer life than standard HPS lighting fixtures and give off lower heat output per watt.