Some mushrooms, such as the Agaricus species commonly found in grocery stores require no light at all. However, those commonly grown by hobbyists, such as Pleurotus ostreatus (Oyster Mushrooms), Lentinus enodes (Shiitake), Psilocybe cubensis, a hallucinogenic mushroom, and Hericium erinaceus (Lion's Mane) all require light to produce abundant, normal sized fruits. Experience has taught us that the light best suited for primordia formation and the development of fruitbodies is bright light with a color temperature of 5,000 Kelvin to 7,000 Kelvin. Fortunately, this type of light is easily obtainable at your local home improvement center in the form of fluorescent fixtures. For a small terrarium as described in this chapter, a single CFL (compact fluorescent) that screws into a standard light bulb socket will work very well. These can often be found in grocery and drug stores in every neighborhood. 15 watt CFLs will do the job well, but the package will probably have a large 60 stamped on it, indicating they produce light "equivalent" to a 60 watt incandescent light bulb. They're referring to lumens of output, not the frequency. Incandescent light bulbs are the worst possible choice for growing mushrooms, since they emit a 'red' light in the 3,000 Kelvin color temperature range.
The higher the color temperature, expressed in Kelvin, the closer to the 'blue' end of the spectrum the emitted light is. The lower the color temperature the 'redder' the light is. If you have a choice of fluorescent lamps, purchase those labelled 'daylight' since these have a somewhat higher color temperature than cool white. Daylight, sometimes called 'natural daylight' fluorescent tubes generally emit light in the 6,500 Kelvin range, while cool white fluorescent emits light at around 5,000 Kelvin.
If you have several terrariums stacked or otherwise near each other, you can use larger 2 to 4 tube fluorescent fixtures. These come in 48" and 96" lengths. Place the fluorescent lamps as close as you can get them to your terrariums without causing excessive heating. Species such as Shiitake and Oyster mushrooms prefer to fruit at temperatures in the upper 50's to mid 60's Fahrenheit (15C to 20C), while Psilocybe cubensis prefers to fruit at a temperature in the mid 70s to about 80 Fahrenheit (23C to 27C) Most mushroom species don't mind a slightly warmer temperature during daytime than at night, so if your grow room is a bit colder than the temperature ranges given above, a little warming from your lights during the daytime won't hurt at all, provided you don't let the air in your terrarium get too dry. For cakes, try to keep the humidity above 95%. Cased substrates are a bit more forgiving, but still try to keep your humidity above 90%. 12 hours on, 12 hours off has proved to be a great combination over a wide range of species. Of course, if you have a bright window near your terrarium, that will suffice, but direct sunlight for more than a few minutes per day should be avoided.
Quoted from http://www.mushroomvideos.com/Terrarium-Tek