Introduction

There were two separate experiments we ran in order to understand the performance of our NH-1. The first of which was to confirm that our rendition of purple light was significantly better than an alternative green light. This was a proof of principle, which is meant to outline that a higher Lux reading will result in more germinations. The second experiment was measuring the germinations from the optimal purple light against a simple windowsill (natural daylight).

Method

For the first experiment we had to make a rudimentary barrier to place inside the NH-1 in order to block light effectively. We did this by using off cut plywood and wrapping them in tinfoil to create a reflective surface, sourced from the architecture workshop. Figure 3 shows the dividers used. This allows us to expose different areas of the hydroponics to different wavelengths of light.

Utilising the Arduinos easy to adapt design we can manipulate this device to display the desired wavelengths down to an individual LED. The first four LED’s emitted green light and the remainder emitted purple, the intensities were measure to be 200, 1700 Lux respectively (code can be found here). Seeds were then placed in two 96 well racks, one green (A), one purple (B). They were then left to germinate for a week.

Figure 3. Demonstration of divider being used within the hydroponic system.

Results

It was expected that there would be more germinations from rack B, Figure 4 confirms this hypothesis. The germintations for racks A and B were; 6, 22 respectively. Figure 5 shows the heights of the germinated Arabidopsis phenotypic. Whereas the Rocket in rack B is more uniform. Indicating Purple light is more effective for germinating a higher number of plants. Which at least indicates that the higher the Lux the greater the superior the yield. Confirming why Purple light is used more frequently.

Figure 4. Graphical display of rocket germinations when exposed to green Vs purple light

Figure 5. Graphical display of rocket height when exposed to green vs purple light

Figure 6. Graphical display of rocket germinations when in the NH-1 or on the windowsill

For the second experiment the results are also clear (Figure 6). The percentage of germinations for NH-1 after 4 days were significantly over 50%, compared to the windowsill which were around 25%. The gap slightly closed after 8 days, however the NH-1 was still roughly 25% more efficient. Therefore we can conclude that our system works, it provides a more efficient germination period than a natural counter part (Newcastle daylight). Whilst also allowing us greater control over the day and night cycles, if we need to starve the plants of sunlight we can quite easily adjust the settings.

Conclusion

Both of the experiments provided data that suggests our system is effective at creating a high throughput germinating environment. This system is also controllable and programmable if growing conditions need to be changed. Overall, this system is a success and we have met of our aims which were to provide a guide for a system that is controllable but more importantly worked, and was a suitable substitute for a windowsill.