The Different Grow Room Lights and How You Use Them

The most common grow room lights are called High Intensity Discharge (HID) lights. There are two kinds of HID lights: Metal Halide (MH), and High-Pressure Sodium (HPS). There’s also a “dual spectrum” light that combines MH and HPS properties in one bulb.

HPS bulbs are comparable to MH bulbs, with good spectral distribution, but they lack the metal halide’s intensity at the “blue” end of the light spectrum. HPS bulbs are best used as plants are starting to bud, and can carry through the flowering stages of growth.

Metal halide (MH) bulbs are a long-time favorite among growers, because they provide an excellent spectral distribution. For plants, this is optimal for growth, because MH bulbs mimic bright summer sunlight – and that means that photosynthesis also occurs at high “natural” levels, much more than other types of lights can achieve. These are good for your plants when they’re in their green growth, vegetative state.

Dual spectrum bulbs contain both the workings HPS bulbs and MH bulbs within a single bulb. You can use these during all stages of growth, in that this is a true full-spectrum bulb.

Compact Fluorescent Lights (CFL) and Fluorescent Tubes can also be used in grow rooms. They are cheaper and easier to set up and maintain than HIDs, are good for young plants or clones that don’t yet need a lot of light, and are best for very small “grow rooms” with just one or two plants that don’t exceed 12 inches in height. However, yields are lower than with HIDs because fluorescents just don’t have the intensity of the high power lamps.

Light Emitting Diode (LED) lights have made their way into many grow rooms. Although still developing and relatively new to the scene, growers have been impressed with their performance thus far.