Designing LED grow panel

[sideshowmel]

when I thought there might be "missing wavelengths".

How many wavelengths would you say were absolutely necessary, and how many for the ideal?

What do you think about choosing emitter chemistry based on the highest efficiency available in a roughly similar wavelength versus a less efficient type which is bang-on the photochemicals' peaks ? Does 10-15nm of margin seem sensible to you?

[Weezard]

I get by with 2 now.
Red n blue will do.
Used to try a lot of things
Until I got a clue.

(Sorry, sometimes I jus' gotta.)

But it's a bit less simple in practice.
For instance, I've found a strain that does poorly in veg. with 660nm red, but seems fine with 625nm?!

It also appears that R:B ratio is a player, strain-wise.
Can't tell you much about flowering stage though.
Doing all my flowering outdoors now.
Not that the leds didn't cut it.
They flowered impressively, but the sun is free here, and is almost 12:12 year round.
I jus' filter out the UV and watch 'em frost up with trichs.
Now I don't need to keep two rooms and chase light leaks etc.
(Way to make a lazy guy happy)

And, yes, 10 - 15nm margin is no problem.
Go for efficacy/wavelength.
(The plants grade on a curve)

"I'd really like to hear if anyone has done more specific experiments on these questions. Should do them myself and stop complaining I suppose."

Gobs of it, ad nauseum.
Google "Martian method" It was a great ride with no real destination. IMO
Aloha,
Weeze

[sideshowmel]

The martian thing looks interesting, but not really what I had in mind.

The sort of experiment I was thinking of would involve a set of boxes, each big enough for a small plant, and designed to consume the same electrical watts but produce different light spectra. Maybe have some with 1 red 1 blue, some with 2 red 1 blue, some with added far red and far blue, some with broad spectrum white and so on. Control for temperature, atmosphere, nutrients and growth medium, and then calculate yield per watt hour for each. Of course the comparative efficiency of different LED wavelengths will probably continue to develop over time, so maybe calculate yield per photon flux aswell.

Maybe test two spectra at a time with several under each spectrum. Wouldn't take many seasons to get results with a reasonable likelihood of statistical significance. Could probably do it in a few years if I took a bit of overtime to increase the tinkering budget.

I find the whole subject fascinating, but I haven't had much luck finding data collected under controlled conditions, so it's a good excuse to solder things.

[Weezard]

Pleased to meet you Ssm,

Yer my kine guy.
An' you speak solder?

Box 'em, light 'em, grow 'em, post 'em.
I'd be tickled to assist in such a worthwhile experiment.
My brainstorms may lack some donder n blitzen in my dotage, but I still get the occasional widely scattered showers.

Did you dig for the NASA research?
It's a valid, if linear, pursuit and will save some "legwork".

Gonna be difficult to collaborate on this forum though.
No visitor messages, or PMs.
Might do to move it to a less restrictive board.

The children here tried to commit various felonies when they had PMs,
so management punished everyone by shutting down most of the useful features.
Cdot is kind of a kiddie pool now.
Most of the serious growers have bailed, and moved on to less restrictive places.

I hang on to see if any serious talent stumbles in the door.
This was once a first class board, so we still find intelligent folks that google in to the archives.
(IMO C-dot has the most comprehensive cannabis archives on the web.)

But, the "no freedoms" and the number juvenile postings are starting to wear me down lately.
Aloha,
Weeze