Mr. Nice Forums  
Home History Strains Media Web Community Medical Marijuana Contact us Auctions

Go Back   MNS Forums > Grow information > 14. Indoor

View Poll Results: In your opinion what is the most efficient light source when comparing gram per watt of dried weight
HPS (specify which one on the thread) 6 46.15%
LED (specify which one on the thread, diy, etc) 6 46.15%
CMH / LEC (specify which one on the thread) 0 0%
Metal Halide (specify which one on the thread) 1 7.69%
Cfl 0 0%
Voters: 13. You may not vote on this poll

LinkBack Thread Tools Display Modes
Old 09-11-2018, 06:37 AM
Broseidon's Avatar
Senior Member
Join Date: Nov 2015
Posts: 919

I agree.

To me, the adjustable spectrum alone makes LED the best lighting tech going forward. Combined with the low overhead costs and cost of replacement I agree that it's the tech of the future.

Just gotta figure out when that starts. Up until this year I was certain it was still early adopters stage and you are paying for research, trial and error for not completely established products. But it seems LED has moved past that stage in the last year or so.

If prefabed fixtures are feasible for commercial ops already, I would say we have no more than a few years before LED likely takes over which means likely a decade or two before HPS etc. gets phased out.
Reply With Quote
Old 09-12-2018, 10:19 PM
Big Sur's Avatar
Senior Member
Join Date: Nov 2016
Location: The great PNW
Posts: 417

Still not sold on LED. I voted for MH in the poll because I have a lot of experience using them. However, CMH is obviously more efficient. But efficiency can be factored several ways. As in up front cost, running cost/energy used, light energy produced, light spectrum absorbed, heat loss, or whatever. Obviously the SUN is the most efficient. It is also a constant, in that we are about 93 million miles from it, it is the same intensity (less an unmeasurable minute fraction) on the ground as it is 15 feet off the ground. It also has the full spectrum that plants use. And it is free. People do not seem to understand that growing indoors creates problems with the energy lost due to the distance from the bulbs. Light energy falls off at the inverse square of the distance from the source. Which means that the light energy from a bulb, ANY bulb or LED, is 1/4 the energy at two feet away from it than than one foot away. At 10 feet you get 1/100 the energy from a bulb than one foot away. So you can have the most efficient lighting, but placed too far away, it becomes far less efficient. Also heat produced is not always a loss.

Take my case. I grow with 400w MH bulbs in the fall and winter. So 'heat loss' is not a factor, as I grow in an unheated building and I need to heat it anyway. Heat loss for me is actually a benefit. No A/C is needed. I only grow indoors to overwinter clones, to start plants in the late winter and to finish plants blooming in the fall. Otherwise I grow outdoors in greenhouses. I have switchable ballasts and I can run either MH or HPS. I only use HPS in finishing my plants in the fall if we get early rains or cold weather. Otherwise I use MH bulbs as I prefer the results from the MH spectrum. I use 400w so I can get them closer to my plants and they are more modular. They are also cheap. I can get them for near nothing from growers bailing out of the green rush in Oregon. I also pay 10 cents a KwHr here. So each MH bulb is $24 a month to run on a 20/4 light cycle. It would take me years to pay back the higher LED start-up costs and then I would have to heat my grow area, so for me it is not worth it. CMH would cost a lot of convert to as well, but it is more efficient than MH has a better spectrum and includes UV light, which they are finding has benefits for plants when in bloom. I would also get the heat benefit from using them.

So the short answer is that it depends on your growing needs, costs and local conditions.
Landrace and heirloom seed collector/trader.

Last edited by Big Sur; 09-12-2018 at 10:24 PM.
Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT. The time now is 11:50 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
SEO by vBSEO 3.6.0 PL2
All rights reserved, MR NICE SEEDBANK, NL