I have a photo of young tomato plants from a few years ago when I was experimenting with combinations of height of the LED strip and wall watts. This photo has 4 combinations. Single strip height (from ground) at 12″ and 24″, 8 and 16 wall watts. The “grow chamber” are very cheap. Much cheaper than the wire shelving unit I currently use. But they were very flexible and changing strip heights was very quick and easy. I use 3M Dual Lock Reclosable Fastener tape (velcro like) to fasten the strips.
https://www.yborfarms.com/growLightExperiment.jpg

My strips are easily replaced in the field. They are mounted to three 24″ strips of aluminum per 14″ x 30″ shelf tier.
I use three standard 1020 trays with the 10″ tray width across the 30″ shelf with the 20″ tray length with 3″ of the tray hanging over each end to the 14″ shelf.

When using strips the grow area is reduced by 12″ (2×6″) on each end of a strip of LEDs.
I previously used a 27″ x 17″ germination tray. I have an app that creates a heat map of the uniformity for a fixture of strips. This is an image from the app for the 27″ x 17″ germination tray. The strips are 44″ long with LEDs right up to the very edge of the strip. The first line at the top is the width inches of a 24″ x 48″ grow chamber. So there are 2″ between the end of the strip and the edge of the grow chamber. Notice how the area from 10″ to 36″ across has near perfect uniformity. But that’s only because the 44″ strip extends over 8″ beyond the tray on both ends (44-27) = 17″ and 17″÷2 = 8.5″ each end). When you buy a rigid fixture for each grow area (e.g. a single shelf) the is a lot of waste.
Let’s compare a 24″ x 36″ grow area (e.g. a grow tent). You buy a 24″ x 36″ fixture and you get good uniformity for only a 24″ x 24″ area if the fixture is 36″ long.

With my design I have 44″ strips on a 36″ shelf. Ugly with the ends of the strips sticking out? Yes, but if you put the shelving unit side by side and get the ends of the strip to butt up against each other you just increased your grow area by 12″. This works very well with large industrial shelving. But I’m cheap. $60 vs. $300 per self. And I lose 6″ for the
I could explain the uniformity app but that would have to be full article. The app was verified with a StellarNet Blue Wave spectrometer.
https://www.stellarnet.us/spectrometers/blue-wave-miniature-spectrometers/
I measured various points on the floor of the grow area, compared them to the app, and the accuracy was within a couple of percent.
Testing the app was not easy. First off there was no way to verify my equations online. So I made an app for that where I compared my equations, for each wavelength, with the measurements of the Blue Wave spectrometer. http://www.growlightresearch.com/ppfd/convert.html
I have many apps. This one compares individual LED’s radiant distribution: http://www.growlightresearch.com/ppfd/dangles.php#
I have build strips with many of these LEDs.

And this photo may give you a better idea of what I am doing. http://www.yborfarms.com/MarketExhibit.JPG
The tray of seedling was one of the first I had grown and got a bit raggedy being hauled back and forth to the farmers market.
I was doing market research at the farmers market.

After taking some time to consider your points, we agree….kinda. Technically you are very correct, we do not want to argue those points.”

We just think you might have stopped short of what would be needed for most commercial farms/greenhouses. The requirement of a heatsink will depend on how hard you drive the diode. The need for a more robust “fixture” will depend on how much light you need to create, where you need to hang the light and what environment you are placing the lights in.

Choosing to build a fixture will help you gain in reliability (defined as performance over time.) Please consider that a slightly less efficient fixture that is built to last, might actually be more efficient over time. You might be able to tell that as a company Urban Ag News also wants to keep the “environment” in mind as we think about business decisions.
We feel a big part of this is buying equipment that will be kept in use for a longer time. We think that a well designed fixture capable of withstanding the highly variable conditions in many production environments will lead to less replacements and less waste generated. That is important to us.

BTW, we sent an email to Kevin. Hoping to get some feedback from him in the New Year.

Thank you for the detailed response. Our owner knows Kevin very well.
We also remember that paper. Thanks for helping us connect the dots and best of luck with Ybor Farms.
We are going to take some time and think about your response.

I would love to use OSRAM and Cree deep red and blue LEDs. Most µmol per Joule. But the white strips made by Samsung and Bridgelux are very efficient too. Some have a spectrum very similar to R/B and require no heat sink.
yborfarms is a new venture that will grow edible compact vegetables for containers indoors under LEDs. The website is under construction.
Most will range in size from 8″ to 24″ when fully mature. Lots of tomatoes and peppers. Cucumber, herbs, peas, broccoli. All will grow well on a balcony or patio. Gardeners can buy plugs or transplants to plant in their own garden.
I will be using industry standard 1020 trays to grow plugs (128 per tray) and transplant them to 3.5″ sq pots. Then into the final (3-5 gallon) customer decorative planter. I will also sell them as plugs or transplants (3.5″ pot).
I am using inexpensive 5 tier wire shelving with the LED strips attached to the bottom of each shelf. Each shelf has it own driver with adjustable current. I created an app that finds the ideal height and placement of the strips.
I am using Bridgelux EB Series strips powered with Mean Well drivers.
I was a consultant to the University of Florida Horticulture Dept building custom LED fixtures for their grow light research.
I have been researching LED grow lighting, heat transfer, and plant physiology for over five years. My background is biomedical and electrical engineering.
I use white strips because blue and red LEDs are too expensive and run too hot. By using mid power LEDs the heat has much better distribution.

I do have a great design for red and blue strips and have built a bunch using Oslon SSL 150° and Cree with very efficient natural convection heat sinks. Just too expensive to manufacture when compared to using white strips. I pay about 9¢ per kW. The little electricity I would save with the Red and Blue would not pay for the extra expense for the initial cost of the assembled strip and heat sink.

When at the University of Florida I reported directly to Dr. Thomas A Colquhoun and Dr. Kevin Folta two of the authors of this research paper on light recipes for Sweet Basil. I also worked on some projects with Michael Schwieterman.
The light spectrum affects the secondary metabolites (e.g. phenylpropanoids phenylpropanoids, monoterpenoids) produced by the plant. These are responsible for the scent and flavor. See Figures 3 and 4.
Figure 2 shows how well the various light recipes did with respect to plant size and color.
In my opinion BRY is the stand out recipe. Better than GH and RB.
The BRG looks pretty good also. Showing the yellow and green are not a waste photons.

https://www.frontiersin.org/articles/10.3389/fpls.2016.01328/full

Dear Ybor Farms:

We tried to learn more about you and your farm by visiting the website you have listed, but it’s not showing as valid? Is there a typo?
We would like to better understand your comments.

Are you referring to the diodes themselves? If so, companies like OSRAM offer products like the OSLON Square Hyder Red (4th gen.) Very reliable and highly efficient.
Cree, Samsung and others also make great products specified for commercial horticulture needs.
We do understand that there are significant delays in the supply channel, but these companies do make quality products?

Or when you say strips, do you mean a fixture?

With a little more detail, we might be able to provide a better response.

Regarding your trials of different lighting options, do you grow in a greenhouse? Or indoors?

Thanks for the comments.

-UAN

The “burple” lights will do fine inside for succulents assuming you have the right light intensities and a color combination that is about 90% red and 10% blue. (Does not need to be exact.)

The big question is do you like the “burple” color? If you do, give it a try.

Its hard for us to tell you what distances to mount the lights because that is based on intensity of the lights which is based on wattage.
We think you would be safe with 60-90 watts of LED lighting mounted about 20-24 inches from your plants. Photoperiod will be safe at about 14-16 hours per day. (Assuming they are getting zero sunlight.)

Good luck growing!

Is there a chance? Yes. In fact we know plants respond to a wide variety of wavelengths within the spectrum. But, please remember that this article is written based on LEDs being used in a greenhouse where the plants are receiving a wide spectrum of light produced by the sun. The main limitations to light will be geography and choice of glazing for the greenhouse. LED grow lights in the greenhouse are supplemental to the sun. The sun is still providing much/most of the energy plants require to grow. Most importantly, sunlight itself is not constant. The quality of light you receive looks very different depending on time of day and atmospheric conditions.

Also remember that this article is not specific to any one variety of crop, that all crops are going to have different requirements when it comes to light and more importantly all light is not good light.