Which light is best for large scale growing? LEDs? HPS?

[BoMo12]

With so many light options out there, what is the best for large scale growing. Do the benefits of LEDs outweigh the upfront costs? I'm also wondering what specs are the most important. Is PAR the most important spec when choosing a high quality light?

Thanks in advance for all your help.

[BoMo12]

Or maybe a better question...what lights do you use? What are the pros and cons of your lights?

[DrPhoton]

Id recommend looking at some of my articles in my signature.

To answer your question, double ended fixtures are still chosen over most technologies for commercial grows because they provide the best fixture cost per mol and top grade efficiency. Others are adopting LED technology but this is a personal preference choice and not a economical one.

For smaller grow environments, other grow technologies such as ceramic metal halide and LED offer more value to consumers for other reasons such as practicality, longevity, efficiency etc. So it really depends what your looking for.

The gold metric for quantifying light sources is PPF (Photosynthetic Photon Flux).

[DoctorJohnson]

I think you're right for now. My guess is that within five years LEDs will take over as costs drop and efficiency increases, but for now it looks like glowing plasma is still the best bet.

[DrPhoton]

Yes thats right, it has already replaced interior lighting for residential areas. Commercial is now following right behind. LEDs follow the haitz law, which is analogous to moores law. Both rely on the optimization of semiconductors. With haitz law you could calculate when LED would likely surpass other technologies. Efficiency is not the problem, providing that efficiency at economical values is.

[BoMo12]

Thanks, DoctorJohnson and Dangerdan. Sounds like LEDs will be the preferred light in the future once the technology is improved to allow for an efficient product at an economical price.

Dangerdan - thanks for the great articles. I read your "Grow Light Technologies" & "Light Metric Systems". The latter helped me understand how

PPFD, PPF, YPF are quantities for quantifying EMR in the PAR spectrum. If possible, I'm going to try to dial in the levels/amounts that optimize yields.

I'm sure producing optimum yield is a combination of science and art, but for now I'm going to focus on the science portion...specifically how it relates to lights and their current capabilities.

[DrPhoton]

Im glad you were able to extract valuable information from the metric systems article. Your short conclusion from it is very correct. I would like to know your thoughts on the light technologies article. For myself i like most of it, but i am dissapointed in the descriptions of LED and HPS with respect to horticulture lighting. It seems messy and not quite structured clearly enough.

[HydroKid]

I’ve grown with LED and HPS. I prefer the HPS for the simple fact that I had better luck and better quality plants with the HPS. The technology on LED is still coming along at a fast pace. However I’ve seen others produce some great numbers on LEDs. I’ve also enjoyed using light rails with my HPS and it cuts the number of lights required down. My setup has equal plant growth with an even canopy. I have two 1000watt HPS on rails in place of four HPS just because the light rails allow for continued movement. Also helps with heating issues.

[BoMo12]

Thanks, HydroKid. Glad to hear HPS is working well for you.

[Waltermelon]

First I think defining what you consider "large scale" would probably help out a lot with folks making suggestions.

[BoMo12]

Dangerdan, I found the Light Technologies article very helpful. It filled in some information gaps for me personally. Some of my research wasn’t as thorough or complete. Your article did a nice job of covering all aspects. I gravitated to the LED and HPS portions, but liked it all. Thanks again.

[BoMo12]

Good call, Waltermelon. I am thinking roughly 5000-10,000 square feet. My focus would be identifying the BEST light possible to produce optimal yields for an operation this size.