Growing cannabis indoors requires lots of light: Firm buds glistening with resin require a stronger light source than your average house plant.
Lighting for plants is nutrition; it's very much like fertilizer, except it's absorbed in wavelengths through the leaves. Think of a rainbow: each color is like a different nutrient for your pot plants. Each color is important, but various types of plants use nutrients differently; they also use different amounts during different times of the year. For example, in the vegetative state, plants prefer more “blue” light,” while in bud they do better with more “red” light.
There used to be very few choices available for indoor growers -- today, there are many. HID (high intensity discharge) lighting is the standard for more “serious” indoor growers, and High Output fluorescents are a great choice for a smaller-scale hobbyist or outdoor growers looking to raise transplants indoors before the season starts.
Over the past several years there have been improvements to industry standards in regards to crop lighting, including digital ballasts (that drive the lamps) and a wider range of horticultural lamps.
While there have been strides forward, it's still the same technology. One of the reasons growers find HID lighting so reliable is because it is standardized.
For some, that's just fine; especially as declining prices make good lighting more affordable. Some growers, however, are looking to push the envelope of what is possible with cannabis harvests, and as a result, other light sources that are becoming important and becoming more accessible in pricing as well.
Light Emitting Diode (LED), Induction Lighting and Light Emitting Plasma (LEP) are increasingly being adopted for growing indoors by savvy medicinal bud farmers.
Alternative lighting sources may be able to do what HID lighting can't -- and in a variety of areas. It's common practice to discard HID lamps after a year of operation because they aren't as bright after long use. This is costly, and more than in dollars and cents. The arc tubes contain elements like mercury and lead in very pure forms -- so discarding them is terrible for the environment.
HID lighting also produces lots of heat, which can be problematic in a growroom. It usually means using even more electricity to vent it away from the garden. In some instances, where temperatures can't be maintained below 85 degrees with the lights on, it means growing isn't likely to be very successful.
LEDs and LEPs run significantly cooler, which aid in the formation of healthier plants and lowered energy bills. They are also able to deliver many wavelengths of light that exist in the sun's natural spectrum. In some instances, “over driving” these more exotic artificial lighting wavelengths has proven to enhance crop qualities like density and resin production beyond what any HID lighting has been capable of.
Will it be any single one lighting technology that will replace HID lighting one day? Likely not. It seems a hybrid or blend of these technologies may be the answer. Some growers are already reaping the benefits. While HID lighting is sure to be around for a while still, it pays to look ahead in your quest for the ultimate bud.