"Philips GreenPower LED toplighting was installed and programmed with a customized "light recipe" developed by plant specialists at Philips to optimize the results. Light recipes are formulated by taking into account a variety of factors including light spectrum, intensity, uniformity and relative position of the lamp to plant canopy. These are combined to develop specific plant characteristics such as compactness, color intensity and branch development."

phys.org/news/…

Study finds LED lights provide improved energy efficiency and production for growing food crops in space; March 24, 2016

" Philips LEDs assured the production of 54 grams/kWh of fresh edible lettuce, while the plant grown in the same environment under a high pressure sodium system, managed to give only 24 grams/kWh." greenoptimistic.com/philips-led-crop-grow-space

one kWh for 54 grams of lettuce. Wow, put in those terms, it doesn't sound like a lot, considering lettuce is... water mostly. I'd like to see the number for broccoli.

This is on the Phillips site: philips.com/a-w/about/news/archive/standard/news/press/2016/…

I just happened to come across this and wanted to "put it" somewhere. Since it has hard data, and shows an improvement trend and that cool therm "light recipe" I thought it might be worth at least squirreling away.

solidstatelighting.net/…

@uhoh after some time rooting around in documents like that, finally i stumbled upon the grow-op community, who regularly produce comprehensive articles about the pros and cons of all the many LED grow lights on the market.

that one seems like a good recent article

it isn't as specific or scientific, but it lists the real pros and cons without favoritism. these are businesspeople ;)

@kimholder Side note: the previous link advocates growing substances which are illegal in many countries where people might see this and click on it, and where governments will make a careful note of that click. A thoughtful warning would have been appreciated. Just sayin'

er... not quite a dome! Something seems to be missing!

@uhoh that didn't occur to me, about the tracking part. sorry for the oversight.

i'm surprised the link was removed though.

it was highly relevant, and i have, for instance, linked before to videos of people shooting at each other, in real life, that that stayed.

i might have chosen instead to add the warning, like you said. where i come from 'grow-op' is a common term that means 'growing marijuana indoors', and i'm so used to it, i thought you'd know the term too. sorry again.

@kimholder I know Midnight Express is just a movie, but it's a big world and even in the 21st century there are death penalties for this kind of stuff.

Anyway, the LED spectra and influence on growth is a bit complicated. I'm going to do more reading about it when I go to the library.

Trying to get to a final answer for this one

the article that was posted talked a little about that, ironically.

it's position was that for the healthiest plants, when they are growing it is best to have full-spectrum lights

then for flowering you turn on the pink lights (which look truly magenta but are a mix of red and blue)

i just went looking for other such articles. they are very heavily concentrated in the marijuana growing community, though. some mention spectra. i'm looking for something that defends the idea that broad spectrum is useful for what they call the 'veg' phase.

though it isn't scientific, it is really hands-on, and it might say something that helps look up a research paper

^ you run across helpful things like that

@uhoh that is quite interesting. i have seen images of that machine before, but never a video. i bookmarked that one.

@kimholder I was really disappointed by the video. When I saw "building" I expected a roof, and was really interested to see a robot build a complete enclosure. But it was "Fake News" (joke, humor) just some walls and a big opening for the robot to drive out of once it was done. :(

It's late, gotta sign off for now...

good night