Hello again LED enthusiasts. I had to drop out to deal with work and also to try to understand why everyone is so interested in bashing in the forums. If you are interested in having a discussion about the merits of lights and their ability to grow I am all in for that. Thank you to those of you who contacted me via PM to express your concerns about the posts after I joined this thread, it is what has brought me back to try to talk again.
At the end of the day aren't we all interested in results? Unfortunately I cannot give out some of the information requested. We have spent over three years researching and conducting our own research on growing with LEDs and it would not be prudent as a business to give away what is one of our largest advantages. Many of the companies mentioned in this thread haven't been around for most of the time it took us and would love to know the details of our spectrum and other hard earned knowledge. I hope you can understand this.
All of our work at Black Dog LED has reaffirmed our belief that to be the best light you need two things; power and spectrum. Power in the form of photons or more simply you have to push some real wattage. Companies that say you can flower a 4' x 4' area with 300-400 or even less watts are flat out lying. The accepted standard for HID is 1,000 watts for a 4 x 4 area and I can tell you that you cannot get a light in that wattage to flower as well as a 1,000. Just not possible. For spectrum, we are constantly working on improving our spectrum and it is one of if not the most complete spectrum on the market. This is not hyperbole, we have a $4,000 spectroradiometer to test light sources so we know that what we design on paper translates to the real world. If anyone has a light that they think has a better spectrum or even a spectrum as good as the manufacturer claims we would be happy to test it as we have for many customers that have walked into our shop.
We believe most LED manufacturers overestimate their footprints and do not have the power to do what they claim in their marketing. We are going to post information regarding this in the coming weeks. We will be releasing PAR values at varying heights and distances from center as has sort of become the standard. To see what I am talking about and to see what we will be comparing ours numbers to, check out the charts posted on GrowersHouse.com (
Hydro Grow Penetrator,
Stealth Grow,
multiple smaller lights,
Solarstorm). The only problem with their numbers is that they may be slightly skewed. Some of the leaders in the field say using the Quantum Sensor as they do in the test at GrowersHouse. The issue is that for very bright light sources (such as grow lights) they are not completely accurate and a spectroradiometer should be used. Of course a Quantum Meter costs less than $400 and a Spectroradiometer costs $4,000 and up.
With regard to this I would like to ask a couple questions for the more educated readers following this thread. We have spent considerable time looking for research on the absolute PAR values and cannot find anything conclusive so I would like to know your thoughts on this.
- What is the maximum PAR that cannabis can can use during flower? By this I mean that at some point you reach saturation and additional light will result in increased yields or quality. I have seen some numbers quoted at 400 and 600 PAR being the maximum, but nothing conclusive.
- What is the minimum PAR for effective flowering? This is a bit more subjective since "effective flowering" leaves some ambiguity but our feeling based on research is that this is probably between 100-150 PAR.
- What is the minimum for effective vegging? Again, a bit ambiguous but I have seen research on this saying that 14 PAR is the minimum for keeping a plant alive and healthy. For effective vegging where you get solid vegetative growth is in the 40-50 PAR range.
We all need a way to measure light sources and while PAR is far from perfect it is light years ahead of using lumens. PAR does have some serious shortcomings but that is another discussion entirely. If we agree that PAR is the best standard measurement we have today, then we need to agree on how to apply it, which is the purpose of my questions.
I appreciate any thoughts you have on this subject.