What is a Kelvin scale?
One way light is measured is on a Kelvin scale. A Kelvin scale expresses the exact color the bulb emits. Bulbs in the range of 2700 to 6500 on a Kelvin scale is ideal for growing marijuana. Plants respond not only to the quantity of light, but also the quality.
* artwork provided by: ReSoNiC420 (click chart to enlarge)
What color spectrums are available in fluorescent bulbs?
Fluorescent bulbs have the most range of spectrums than any other bulb. The spectrum comes in various spectrums, determined by the type of phosphor with which the bulb is coated. The following fluorescent types are as listed, along with what they may accomplish for you.
Full spectrum fluorescent bulbs have all the colors of the Kelvin scale. This bulb is good for vegetation stage. Note: This spectrum fluorescent is used in hospitals nationwide in helping people with "depression".
Wide spectrum fluorescent bulbs will restrict development of side branching, helps plants mature faster. This fluorescent is high in the red, orange and yellow color range. In fact, this fluorescent is the highest than all other fluorescent bulbs. As a matter of fact, this fluorescent is much like an HPS color range, which makes it the best all around choice for flowering stage.
Daylight spectrum fluorescent bulbs are very high (if not the highest) in the blue range on the Kelvin scale. This fluorescent promotes an arctic blue look. I suggest this fluorescent during vegetation stage.
Cool spectrum fluorescent bulbs will promote multiple side growth, nice green foliage. This fluorescent is high in the blue range, giving off a bright white appearance. I suggest this fluorescent for vegetation stage.
Warm spectrum fluorescent, will promote extra thick stems and branches, and will give you about 5% denser buds than other spectrums. This fluorescent is high in the red range on the Kelvin scale.
In the old school of fluorescent growing, an even mix of warm white and cool white tubes has been proven to be the best combination of light spectrums to use for flowering stage. If wide spectrum bulbs are unavailable in your area, then this is the combo to use.