Just FYI, that graphic you display at the bottom of your post may not be the most informative in regards to LED growing and the benefits of full spectrum coverage. Now if we could find a way to achieve the penetrative power of HIDs. Anyway, read this article for some explanations as to why that graphic may not be the most helpful. http://feroled.net/led-grow-lamps-guide/led-grow-light-spectrum/
These may be interesting- The Effect of Electrical Lighting Power and Irradiance on Indoor-Grown Cannabis Potency and Yield. (abst – 2011) http://www.ncbi.nlm.nih.gov/pubmed/22211717 UV-B radiation effects on photosynthesis, growth and cannabinoid production of two Cannabis sativa chemotypes (abst – 1987) http://onlinelibrary.wiley.com/doi/10.1111/j.1751-1097.1987.tb04757.x/abstract;jsessionid=E27DFF97974EDECC7DCDFFD1EED18D17.d03t03
Cool seeing that there are actual abstracts on this kind of research. Also, glad to see that my findings and beliefs surrounding the advantage of introducing UV-B (Metal Halide lighting for those unaware) during flowering helps increase the plants' natural sunscreen, trichomes! That is quite interesting to see that the gram per watt yield was improved with lower intensity lights. That highly interests me doing as one is doing a vertical set up at the moment using one 600W HPS in a space of approximately 3.5 feet of canopy height to cover x ~30" diameter of canopy (doing a vert SCROG), and finishing up a normal horizontal grow in a 5'Wx6'Lx6'H box that will be turned into a vert set up of 4-5 tiers for pots, and will run 1200-1800W. It is noted that the amount of flowers produced increased with higher intensity lights, so if you're looking at this as, "I want X amount of bud in X amount of time" that is an improvement, but at the cost of increased electrical bills. If the g/W is better on lower wattage bulbs, why not have more numerous smaller set ups that equal wattage of the amount being used running 600 or 1000W? I guess at that point space is the issue at hand, but this would defeat the, "I need more NOW," argument. I imagine the 600W would be a nice middle ground in expenses and efficiency as 600's put out the most lumens/PAR per watt typically. It would be interesting to set up several 400W (in actuality, 800-1200W with 2-3 light tiers per square footage footprint) verts. One currently runs between 1800-3600W in HID alone in their grows. One could run dual vert set ups with 3 light tiers running 400W per tier and cover 6' in height quite easily.....Oh all the experimenting I would love to see and do, there's always something I want to control test whether it be necessary light intensity, nutrient regimens, etc. EDIT Also, I found the entire document that contains the abstract you listed; it was so interesting I had to search for more https://docs.google.com/file/d/0ByW-RytTeYMQMTc3M2MxYzMtNjUxZi00ZGZhLTg0YWMtYjAzMzNjNGY5NDEw/edit
Hi everyone, I'm new here. Ive read through this post and have gleaned a lot of information and had a few good laughs along the way lol. My question to all of you is if you had 2,000 dollars and a 5x5 tent would you invest in a black dog platinum 750 led, California light works solar storm 800, lumigrow 650, or plasmagrow light gen2? Whatever system will be supplemented underneath the canopy with agromax 4' led white strips to ensure penetration. One in each corner. I am really leaning towards black dog, Ive seen good results from them in a couple grow journals. Thanks for any help I know it takes time and I really appreciate it. Sent from my XT1080 using Grasscity Forum mobile app
So the original Q was about ideal lighting spectrum. Im i fan of LEDs myself, and although those who responded above that using 660nm red and 450nm blue are correct, what you really want is full spectrum. Building the LED array yourself isnt hard and will save you literally thousands of dollars. Get the 380nm-840nm full spectrum chips and you can build yourself one hell of an array. Ebay has it all.