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Basics of lighting, the start of a primer

Continuing the discussion from PPFD Grow Light Comparision:

I am starting this thread to collect hard science of lighting. Eventually we will collate the information for the growers library.

I am looking to afocus our efforts on the following. Please expand if necessary.

  1. How to choose lighting vendors. Hard questions, not I am a better vendor. The whys.
  2. How lighting is effective in glasshouse production.
  3. The differences between glasshouse and grow room requirements.
  4. Hard science behind lighting sources.
  5. Cost benefits of the business of lighting on production. Business side of lighting as a function of production. How to ametorize lighting. What does it do to your production costs from an overhead cost calculation. The best number I have is 1 cent per square foot per day. So we can use 23 vs 24 cents as a starting point.
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@Theo, can’t you add here.

I need someone to transcribe you YouTube talks. There is a free ADA application for close captioning the videos they can give you the script. You will need to edit the output for correctness.

Ethan, we live in the video age, People don’t read a lot any more ;). The information I provided in those videos is not unique, there are more than enough resources on-line that discuss PPF and PPFD, for example this one:

A moderator btw already split the topic. - you are starting a new one now and refer to a topic that will soon have no reference to this topic any more :wink:


I am of the age where reading holds my attention. A video is an okay teaching tool. I like seeing how you do the testing. But, it’s a poor way to learn science.

I like to see more on spectrum analysis. I still remember having to photograph mass spectrometry results with film. That is a celluloid based plastic product covered with a light sensitive emulation::stuck_out_tongue_winking_eye:. We even had to develop our own negatives.

From the voices in my head

Nice refresher on basic lighting. Do you have more references on basics of lighting? And the choices involved in deciding on a lighting vendor and sources? I have not purchased lighting since the 1991. I would like to understand the changes in technology and efficiency. I know from my past experience in supplemental lighting of Lathersus oderatera only added 1 cent per square foot per day to our overhead production costs. 21 cents to 22 cents per day when in operation. But, we saw a 47% improvement in production output. We messuraded total available, photosynthetic radiation below the saturation point for the crop and added light to make up the difference per day. It was a big pain running the calculation in 1990. How is this accomplished today? We where highly automated for the time, but we would have to manually adjust the lighting schedule to get to our daily goal. Would be nice to add light on a cloudy day for a crop. Or additional lighting to reach a photosynthetic goal level for the day. This would simplify the production scheduling goals.

I can see adding this type of data as a weekly item tracked in a production log.

The USDA in the states tracks available photosynthetic radiation at lots of locations. But, the data is only calculated on large agronomic crops as a commodity perdition tool.

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yes I have. We already published some articles I wrote and there is a good paper on how to position lighting, though that is specifically written for our fixtures and reflectors. In general though, for any horizontal lamp fixture, the spread is not square and not a 4x4 or a 5x5 like many think it is.

Here you will find the papers and the articles (more to come soon):

Oh, and of course our YouTube channel.

However, I believe that should be part of a separate discussion. Maybe a moderator can split these two posts to a separate topic about Lighting Basics. This is not a response to my response.

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Thank you. I am looking for reading to quote. Or transcripts of the YouTube videos.

I agree separate discussion. @nicholas, @nick, @Hunter. Please pull the lighting as a new thread.

you can actually quote a video too, by providing a link with the starting point, such as this one (explaining PPF)

We don’t provide transcripts of the videos. Most of those are not scripted at all, it’s just me unwinding :wink:

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