LED help!

[early_bird]

Great commend @C++
As more i dig into this topic as more get´s clear we don´t have a cheap way to measure the light plants can use to compare LED´s.
We can measure the ammount of light with a lux-meter which is cheap an available.
While this is giving us a idea about "how much light" is hiting a certain surface it doesn´t help to compare different light sources like LEDs in my opinion and i want to explain why, sorry this get´s a little technical.

For this we need to take into account a few more things.
First is we need to ignore all lightening below 380 nm and above 780nm which a Lux-meter doesn´t do (a a PAR-meter would).

Second we need to consider photons at higher wavelength has more energy.
So we would "weight" a photon with 380nm wavelengt with a factor 0.6 while a photon with 780nm is factor 1 worth. Means this photon "counts" more giving, or say it so, give the plant more energy than a photon with the 380nm wavelenght which contributes just 60% of the photon in the 780nm range giving the 100%.
Short said: Higher wavelengh = more energy.
A luxmeter doesn´t take this into account i guess.

And now comes part 3, at which not only a lux-meter, also a par-meter would suck.
Our favorite plant uses the light a the lower blue spectrum as also at the higher reddish spectrum, ignoring most of the light in between. So to measure and compare different light sources like led´s this would be neccesary. A light source which produces light which the plant just ignores would be useless but this is measured by a luxmeter device so we get a wrong measurement.

This are the reasons while measurement with this devices is may a very useful thing and can be very helpful comparing distances for lightening of the same light source, it´s completly useless to compare efficiency of different light sources with each other. Behaviour at different Spectrums are the reason for this.

See also:

Measurement of PAR (Photosynthetically Active Radiation) Gigahertz-Optik

This technical article presents the theoretical fundamentals and metrological implementation of photosynthetically active radiation (PAR) measurements.

www.gigahertz-optik.com

 

[Dnzl]

Damn Early Bird you made me think a little to hard on that response, time to medicate! I received my lux meter a few days ago and used it to set light height. I have 5 lights in my flower tent so it was rather helpful since I don't keep a even canopy. When I fill the tent with 4-5 plants it will be very handy to get each plant dialed in. I am liking LED lighting just still unsure of spending the money on a "good" light. The idea of being able to set different heights using multiple lights sparks my interest.

DNZL

 

[yesum]

I think the plant uses all light from the sun, all the spectrums. Never bought into the blurple stuff, blue and red and ignore the rest. The plants evolved under the sun, why would they use a small fraction of the light?

I understand you can grow with limited spectrum, but ideal chemical balance in the cannabinoids and other stuff in the plant to help the high be the best it can be.

 

[Pumpkin]

You mentioned you used HPS, to keep things simple you could run full power and raise and lower the lights as you see fit. When you get a feel for that, maybe the dimming schedule will become apparent. I only got LEDs recently (so have zero experience with them) and that is the approach I'm thinking of taking.

 

[Corpselover Fat]

I think the plant uses all light from the sun, all the spectrums. Never bought into the blurple stuff, blue and red and ignore the rest. The plants evolved under the sun, why would they use a small fraction of the light?

I understand you can grow with limited spectrum, but ideal chemical balance in the cannabinoids and other stuff in the plant to help the high be the best it can be.

They don't use all wavelengths from the sun, but the visible range they do. From the studies I've seen spectrum is not a huge deal for the cannabinoids nor terpenes. There are some effects, but not that much. Spectrum seems to affect plant shape mostly - blue makes for a compact plant while red promotes cell expansion. You can't grow cannabis in monochromatic light, but beyond blue and red the rest is *mostly* just more photons for photosynthesis.

Also there's no reason to think the sun is the best possible light source anyway. Cannabis has not evolved to produce the most pleasant high for humans. The chemicals it produces just happen to have the effect on humans. It also hasn't evolved to produce bountiful sensimilla either.

 

[exoticrobotic]

Try a grow of clones with SUN,HPS, CMH, LED, FLOURO and see if they turn out the same. They do not.

Also there's no reason to think the sun is the best possible light source anyway. Cannabis has not evolved to produce the most pleasant high for humans.

The blessed weed evolved under the sun? It's done a pretty fine job of evolving to give me a pleasant high.

Evolving to give humans a nice high is a very effective way of greater seed dispersal and hence survival.

 

[exoticrobotic]

.

 

[exoticrobotic]

I am liking LED lighting just still unsure of spending the money on a "good" light.

Did you notice any difference vs HPS?

Plant growth/high?

 

[Corpselover Fat]

Can you provide links? Not light mfer sponsored ones.

I don't have other links readily available other than a one sponsored by Valoya (a led company). I see nothing wrong in the methods though. You can find Bugbee's studies easily. On the other hand Grow lights australia did find a small increase in THC using near uv.

Light spectrum is obviously very important to both cannabinoids and terpenes. That's why we keep seeing new lights being pushed on the homegrower

You have much too much faith in the industry...

 

[exoticrobotic]

You have much too much faith in the industry...

I'm old skool with zero faith in anything canna related this side of the year 2000... - when plant feed went from 2 part to 8 etc etc

Having great results with my old hps and canna one part feed

 

[yesum]

You have no idea if they use something not visible. At this point yes the sun is best in effects. You are not a plant but a corpselover.

 

[exoticrobotic]

Grow lights australia did find a small increase in THC using near uv.

My cynical mind thinks that high thc levels with uv and high cbg levels seen with led grown plants dont address the symptoms i expect and usually see cannabis address.

I must be smoking cannabis for the other cannabinoids other than thc and cbg.

 

[Ca++]

All radiation from the sun isn't useful. Like us, they evolved here, having to work with what is good, and survive from what is bad. UV for instance, has a negative effect on most things. Most recent studies are showing a dislike for blue. It reduces cell elongation and leads to tougher growth. Some other plants have learnt to use it, but ours has survived for different reasons. For us, it buggers our eyes up, and stops us sleeping. Yet we get depressed without it. The idea they like it because it's always been there, isn't a good one.

We don't really understand light, so any deep reasoning is just theory. If you look at harmonic products though, there is a picture of why blue might be so well absorbed. To take in red, the interference from blue might be unavoidable. Hence these protection effects that lower the light getting to the plant, when blue is high.
Green has less interaction with the plants, so gets deeper before it's fully depreciated/captured. The far reds follow the same pattern. If we look at a single leaf, then yes red n blue are captured more than other colours, but with a few leaves, we capture it all anyway. This presents a viewpoint I have not seen thrashed out. Though we do see most triggers are centered around blue and red anyway, so a good dose of green, even if absorbed, isn't doing a hugely useful job. It would be nice to look at the blue responses in more detail though. As using green, we can work on them aqua blue area peaks, while not exciting the more purple ones. Which is really looking like the bad end of the spectrum.

If blue is countering red absorption, the burples were never destined to work well with canna. Using them, or the more damaging UV, might lead to more thc per gram of flower, but if the mechanism was making the flower smaller, such a result isn't great.

I'm back to mixing Sodium and LED for a while. Using the same genetics I used under sodium for years, then LED for years. Which did their best through the Transition. So I'm doing a re-run of those grows, this time with plants accustomed to LED.


What was we talking about again?

 

[exoticrobotic]

I'm back to mixing Sodium and LED for a while.

Any particular reason in adding sodium rather than say cmh?

 

[Ca++]

My cynical mind thinks that high thc levels with uv and high cbg levels seen with led grown plants dont address the symptoms i expect and usually see cannabis address.

I must be smoking cannabis for the other cannabinoids other than thc and cbg.

We need a couple more parameters. Often things that effect plant weight, don't effect it's total chemical yield to anything like the same magnitude. Once we thought that nipping would increase total weight but not the total thc/cbd produced. Similar has been seen when reducing the weight with feed regimes.

If we can annoy the plant, making it do something other than grow buds, then what it does grow, can be more potent. It's unreasonable to think otherwise. I wouldn't say you were being cynical. I think you are making sense

 

[Ca++]

Any particular reason in adding sodium rather than say cmh?

I'm just using what I have. I never did the 315 thing. I might of tried a 630 given time, but LED was always on the horizon, and I had 6s up with no cause to change them.

 

[exoticrobotic]

If we can annoy the plant, making it do something other than grow buds, then what it does grow, can be more potent. It's unreasonable to think otherwise. I wouldn't say you were being cynical. I think you are making sense

Yes, unless the stress causes more fibre and anthocyanins

 

[Ca++]

Yes, unless the stress causes more fibre and anthocyanins

Yes indeed. I'm fighting off the need to sleep, 2 hours before my shift starts. I'm going to fail hard at work today.

 

[Corpselover Fat]

All radiation from the sun isn't useful. Like us, they evolved here, having to work with what is good, and survive from what is bad. UV for instance, has a negative effect on most things. Most recent studies are showing a dislike for blue. It reduces cell elongation and leads to tougher growth. Some other plants have learnt to use it, but ours has survived for different reasons. For us, it buggers our eyes up, and stops us sleeping. Yet we get depressed without it. The idea they like it because it's always been there, isn't a good one.

We don't really understand light, so any deep reasoning is just theory. If you look at harmonic products though, there is a picture of why blue might be so well absorbed. To take in red, the interference from blue might be unavoidable. Hence these protection effects that lower the light getting to the plant, when blue is high.
Green has less interaction with the plants, so gets deeper before it's fully depreciated/captured. The far reds follow the same pattern. If we look at a single leaf, then yes red n blue are captured more than other colours, but with a few leaves, we capture it all anyway. This presents a viewpoint I have not seen thrashed out. Though we do see most triggers are centered around blue and red anyway, so a good dose of green, even if absorbed, isn't doing a hugely useful job. It would be nice to look at the blue responses in more detail though. As using green, we can work on them aqua blue area peaks, while not exciting the more purple ones. Which is really looking like the bad end of the spectrum.

If blue is countering red absorption, the burples were never destined to work well with canna. Using them, or the more damaging UV, might lead to more thc per gram of flower, but if the mechanism was making the flower smaller, such a result isn't great.

I'm back to mixing Sodium and LED for a while. Using the same genetics I used under sodium for years, then LED for years. Which did their best through the Transition. So I'm doing a re-run of those grows, this time with plants accustomed to LED.


What was we talking about again?

The Valoya sponsored study came out with the same ammount of cannabinoids for hps and leds (one which looked like 4-5000k and one which seemed almost blurple). Led buds were slightly smaller, but it was offset by them being a little more potent.

Even if they weren't more potent there might be benefits from the compact plant size. If you have unlimited space it doesn't matter if the plant gets huge, but growing in set area you may be able to grow more bud in the same volume. The fact the leds don't produce infra red also helps growing a lot of bud in a confined space. I grew a pound in my 2*4 and I think it would be more difficult to do using a HPS.

 

[Ca++]

First thing I noticed sticking an HID up, was the welcome ballast start-up noise. Second thing, the heat stress