During Vegetative Growth of Cannabis Plants, Which CFLs Work Best?


vegetative growth of cannabis


Which CFLs Do Work Best During Vegetative Growth? 

(And what the heck is vegetative growth?!?)

The “vegetative phase” of a Cannabis plant is arguably defined as, the time in which a plant experiences rapid growth of foliage, often after the 2nd week from the seed sprouting.

This stage determines whether or not you’ll reap any rewards in the end.


As the most crucial time of plant development; the foliage developed during vegetation will prove to be all-so-precious, during flowering. Mess up during vegetative growth of Cannabis, and your harvest is toast before it even began!




Therefore, it’s important to know which bulbs will make your investment in time, money and effort well worth it. Since after all, if you keep your plant healthy, green and happy in veg, you are several months away from ‘weed heaven.’

For the vegetative stage of plant growth, “red and blue bulbs” work well. regardless of Internet paradigms and what the trolls claim in shouting matches. I’ve grown plants using just 2,700K bulbs and the plants were still short, stout and did not exhibit any abnormal stretching.


Red-spectrum bulbs are known to induce unwanted stretch due to the hormonal response to the red/orange/yellow spectrum. This may or may not be a fact, because other factors  are always at play and people often blame the most “likely” culprit.  So, stretching under predominately red-spectrum light may be due to attributes of a particular strain, and its tendency to respond differently depending on spectrum.


Using predominately blue-hued light during the vegetation stage of plant growth is “said” to keep plants more stout, with a concentration on developing foliage and branching outward, instead of growing more stem and shooting upward–with more space between nodes.


Ample amounts of blue light is given off by bulbs in the 5,000K to 6,500K range, commonly known as Cool White and Daylight,
respectively.  While blue light definitely affects growth during veg, there is no way to determine how this spectrum universally affects all Cannabis plants.


There will be differences depending on the strain, growers, environment and more. At the same time, many strains perform very well using a mixture of blue and reds during vegetation, with the emphasis on blue. A “natural” spectrum would consist of 3:1, or a 2:1 ratio of blues to reds.


Final thoughts?

A true side-by-side comparison, for EACH individual strain, using the same exact medium, nutrients and other “controls,” is needed to tell how two of the exact same type of strain grow differently depending on the CFL light spectrum.

Now repeat after me:  “Which CFLs work best during vegetative growth of Caannabis?”   BOTH!




By Robert Narley