I began running the experiment in early March, within twenty-four hours the control LED module started to burn out. First one line of LED's then another and another until only the centerline of LED's, the two blue and one green LED kept lit.
I kept the experiment running because I still had my second control group growing under the fluorescent lamp.
In the interim, I was worried about the experiment LED module burning out. However, the experimental LED module has kept running successfully for over two weeks without (as of yet) any ill effects. The 50% duty cycle allows the LEDs to cool off before thermal run away occurs.
To circumvent this problem, the manufacturer of the LED's advised not to mix different LED's in the same line.
2nd LED Matrix
From the information gained in the first run, I redesigned the LED matrix (see figure 5). I discontinued using the green and yellow LEDs. (The plants didn't appear to be attracted to them). I used just one type of LED in a series branch. Preliminary testing on this matrix is showing that it lasts much longer. If you decide to do this experiment use the second LED matrix.
Preliminary Results
The experiment group appears to have grown as well as the control group (see figure 12, above). If one measures and compares height alone, it appears the experiment edged out the controls slightly. However the stem of the experimental plants needed to be supported where the control plant stems were stronger.
| Strobe LED | Control Fluorescent | Control LED |
|---|---|---|
| 2.5" | 2.0" | N/A |
| 2.75" | 2.5" | N/A |
| 3.0" | 3.0" | N/A |
| 3.25" | 3.25" | N/A |
* Leaf Mass approximately equal
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