LED Bloom Booster

The recent warm weather in Wisconsin has me back in the gardening mood and I'm working to finish up some of my Winter projects. One of my more fun projects has been trying to coax my miracle fruit into blooming indoors. Currently, there is a 150W HPS and a 13W 6500K CFL, neither of which emits much light at around 660nm, the photosynthetic sweet spot associated with flowering. So, soldering iron in hand, I went about my attempt of bathing my plants in some red wavelength light. DISCLAIMER: This stuff can be dangerous. You have electricity and humid/wet environments which can be dangerous! If you don't know what you're doing, please, either read till your eyes bleed/you know what you are doing or consult a professional. I am in no way responsible if you harm yourself or start a fire or any other bad stuff. Alright </scary stuff>.

So, here is first light of my lamp -->
Wow that is bright! So how did I do it? Well, there is a great web resource at the  Green Pine Lane Forum with enough reading to keep you busy for a very long time! A simple walk through of what I did though:

1. Attach 9 1W ~660nm to 3"x4" finned heatsink using arctic alumina (Note: most high power red leds are 625nm, there are only a few companies that make 660nm leds and even fewer that make fairly efficient ones).
2. Solder LED's in series 
3. Connect to LM317 circuit with resistor to make a simple constant current driver. This isn't the most efficient system but, I had all the parts handy.
4. Connect the circuit to a 24V power supply. I used one that outputs 1.1A which means I'd be able to very comfortably run two of these lamps off of this supply, if I so desired. 
5. Splice 80mm computer case fan to an old 12V wall wart DC adapter
6. Attach fan to the top of the heat sink and use a fair bit of wire to create a hanging mechanism. 
7. Plug in the fan and power supply and bask in the eerie red glow!

LED light is on the right

I certainly learned a great deal about creating LED lamps with high power LEDs and am fairly certain this won't be my last one (in fact, I already am scheming for a the next one). I'm hoping to boost the overall efficiency of this system but first, I'd like to see if this has any marked effect on miracle fruit production! If so, I may have some seeds to sell in the near future. Stay tuned for updates on this and my other adventures in indoor tropical gardening in the Wisconsin tundra.