Significance

• Grow lights are special because they attempt to mimic sunlight, which allows for the indoor growth of plants that normally only thrive outdoors in sun.
  
  

Fluorescent light

• Fluorescent light is a good and fairly economical choice for grow lights because of their ability to put out as much as 6000 Kelvin, the temperature scale used to measure grow light efficiency.
  
  

High Pressure Sodium

• High pressure sodium lighting, while not the best choice for all around plant growth, works particularly well for plants in the flowering or fruiting stage. The downside to only using high pressure sodium lamps is that your plants will become longer and more spindly than desired.
  
  

LED Lights

• LED lights show promise as a good source of plant lighting for their low heat and energy costs as well as high efficiency. Unfortunately, to get a good LED set up could cost over $2,000 as of 2010.
  
  

Bad choices

• Incandescent lights are typically a poor choice for their inefficiency. It's also unwise to use florescent unless you have a deflector shade shining the light directly onto your plants.