|Posted on Sunday, June 29, 2003 - 12:58 pm:||
Best light source for fruiting. (Experiment results)
The purpose of this experiment is to demonstrate the value of various lights in relation to pinning duration's and fruiting.
Types of lighting used:
100 watt High Pressure Sodium (HPS)
100 watt Metal Halide (MH)
100 watt incandescent Gro-Light
28 watt fluorescent
28 watt fluorescent ultra violet
The fluorescents are of a lower wattage, but remain at the industry standard for lumen comparison with incandescent.
The temperature was kept at a constant 77 degrees and humidity maintained at 95%.
Useable light energy for plant growth is measured in Micro-Einstein's which are micro-mols of photons per meter squared per second.
To maintain consistency during this experiment, the distance between light source and material was maintained at 300 Micro-Einstein's as measured by a borrowed Quantum reader. 300 Micro-Einstein's was chosen as this is the industry standard minimum for indoor plant growth.
10 half pint jars were prepared and inoculated. 3 cups vermiculite. 2 cups brown rice flower. 3 cups water.
Koh Samui was chosen for this experiment because it was readily available and quick colonization. This is my regular spore of choice for experimentation as I'm familiar with its growth characteristics.
All jars were inoculated at the same time from the same syringe using the same spore print. Cakes were chosen to maintain consistency and for easy viewing of pins.
Two jars each were used for each light source in the event of contamination.
The growing area was divided and each sampling was placed in a separate light proof area. Each light source was timer controlled and set to activate one hour every six hours for a total of four daily hours.
A brief description of each will be followed by the results and commentary.
100 watt High Pressure Sodium (HPS) - HPS lights are a brighter full range light with spectrums of white, blue, red and orange. Red and orange are most desirable for fruiting (or budding) plants using photosynthesis. The only problem associated with this light source was the intense heat associated with it. To maintain 300 Micro-Einstein's, a distance of 4.2 feet was necessary. To maintain 77 degrees, the exhaust fans were left on throughout the process and additional air-conditioning was used.
100 watt Metal Halide (MH) - MH lights are rich in white and blue spectrums desirable during vegetation of plants using photosynthesis. Heat was also a negative factor with the MH lamp and a distance of 3.8 feet was necessary to maintain 300 Micro-Einstein's. Again, constant exhaust fanning and AC was needed.
100 watt incandescent Gro-Light - Incandescent Gro Lights produce light spectrums of white, blue, red and orange. All spectrums necessary for vegetative growth and fruiting, but do so in tiny amounts. To maintain 300 Micro-Einstein's, a distance of 4 inches was necessary. A smaller fan was used to dissipate heat.
28 watt fluorescent Gro-Light - The light spectrum was almost identical to the incandescent, with slightly more white light which would benefit photosensitive plants during their vegetative state. The problem associated with this light source was the low lumen output. A distance of 1 inch was needed to maintain 300 Micro-Einstein's. At this distance, temperature was not of a negative issue because of the fluorescents efficiency.
28 watt fluorescent ultra violet - This was a true ultraviolet light source, not the "black light" bulb. Micro-Einsteins for this light source were measured at . 025. Maintaining the Micro-Einsteins minimum of 300 was not possible, but the bulb was still used and placed as close to the birthed cake as possible without touching. Less than a quarter inch.
My original hypothesis was that the lumen intensity of the HPS and MH would induce faster pinning, but was demonstrated wrong.
With the exception of the ultraviolet lamp, each of the remaining four light sources had near identical pin growth, timing and fruit completion. Pins for each were plus or minus 4.
Each pinned within 24 hours of the others with the fluorescent pinning first followed by the MH, incandescent and HPS.
The ultraviolet lamp slowed pinning and stunted carpophore growth.
For green plants that require photosynthesis an incandescent or fluorescent Gro-Light would work well with germination and seedling stages, but the low lumen output would create stretching of vegetative green plants as they grew taller in an attempt to gather more light.
For green plants using photosynthesis, they thrive with white and blue spectrums. A MH would serve this purpose well and would also produce acceptable lumens to reduce plant stretching. Fruiting green plants would thrive with a spectrum of red and orange. For this reason, switching to a HPS or supplementing with an HPS during fruiting of green plants would benefit most.
My findings for this experiment was that no light source had advantage over another in pinning or fruiting. Additionally, there were no noticeable differences in potency or yield.
I've been using a weak 50 watt incandescent bulb set to activate for one hour every six hours for a total of four hours daily. After my demonstrated results I will continue to do so as there is no advantage given to any tested light source.
Ainasko is my name backwards. I'm a girl!