We get more calls and e-mails on this topic, more often than one would think…
In general, the principle of using fiber optic components (with or without halogen light sources) as an illumination source to grow plants (or funnel sunlight into dark spaces for the same purpose) has some technical merit, but offers zero potential from a cost perspective.
The spectral content of the Halogen lamp is OK (plants need blue light for vegetative growth (although not too much blue light in Halogen lamps), and red light for flowering (lots of red light is available). Even more appealing is the technique of filtering out IR radiation (lamp or sun) using a filter… and you can be really efficient using the light coming from the fiber, because you can aim it.
However, the aforementioned positives are neutralized by several factors. First, there’s inefficient light transmission; about 35% of photonic energy striking the face of a fiber bundle never makes it into the fiber. Of the 65% that is collected, at least 4% more never makes it out. If you need a deeper understanding, see the technical section on Transmission loss in our website (www.fiberopticstech.com)
Furthermore, unless you use a focused lamp or special collection optics, the amount of energy striking the fiber (and thus transmitted) is very small relative to what is available. (i.e. a 12 x 24 basement window offers 288sq.in… a .5″ fiber bundle only provides .196sq. in. of surface area! (.06%)
BTW, focusing optics have been tried several times… in conjunction with parabolic collectors on the roof. They have proven to work….. but you need to get a price quote to realize the ROI (it is not quick or even worth considering unless your environmental concern overrides the financial considerations.)…and you still need to deal with weather (or night time) raining on your parade… (OK, some pun intended)
After adding up the cost of equipment to overcome the performance inefficiency, and adding in the cost of fiber optic light guides, most budding entrepreneurs give up on the idea….and we agree. In the vast majority of applications, windows, flood lamps or “grow lights” are still the most efficient, and by far, the most economical means to provide light for growing indoors.