LED and BUD QUALITY

[hillbil]

Lights with high “blue” values tend to have a purpling effect, could see leaf shade that stayed green. I noticed it about 14 years ago with Philips CMH 4000K. You could see serrations in the leaf where it shaded stems.

 

[Storm Shadow]

LED tree lacks that extra gear that’s sends you to the next level …kinda meh for effects … but yield and electricity cost outweigh that to 98% of people

 

[Dequilo]

…kinda meh for effects …

they have been good to veg with after figuring out how to use them

I have a run of Autos to try under LEDs so time will tell

electricity cost

somewhat

all the best and grow well

Dequilo

 

[Ca++]

This thing that its P is hard for me to swallow; purpling happens where the light hits the plant. If you tape up a portion of the stem and then the stem turns purple youll see that the taped up portion where no light hits is still green.

There is a big gap in what's understood. Leaving a few reasonable explanations. I might as well make one up myself.
Sugars are moving around in these twigs, and a few things are needed for steps in the conversion. Before the colour is made, and fixes. One is oxygen from photosynthesis. The twigs have higher brix than the leaves, which in turn are better adapted to expelling the oxygen. Survival advantage to leaf.
Excess sugar is less likely if the plant has it's P. In fact, low P causes higher brix. There is a strong relationship between the sugar sat around, and it's use, which P and temperature are good regulators of. These are all pointers seen in the last page or so of replies.
There is no text I can point to. Just a sea of knowledge with puzzle pieces scattered about.

 

[Hammerhead]

Same genetics different phenos diferant areas of the room. Same feed 1.3ec. Same PH 6.4

This plant is directly under CMH.. She just started getting alternating RO feeds.

This plant is directly under HLG. This one no RO is needed.

 

[Deleted user 90433]

In my experience with the strains I run I get these results, that are backed up by what bugbee says.

You’re right, I start seeing light stress around 700ppfd without co2. However I still get yield increases up to around 1000ppfd without co2.

The best looking plants don’t always produce the best results.

I can agree with you on that,looking good doesn't mean it is good,but with 6 different strains it is a average ppfd as some burn easier than others,once I get amber trichomes I know its close

 

[Prawn Connery]

Lights with high “blue” values tend to have a purpling effect, could see leaf shade that stayed green. I noticed it about 14 years ago with Philips CMH 4000K. You could see serrations in the leaf where it shaded stems.

Growers forget that not all PPFD is the same.

Photosynthetic Photon Flux Density obviously counts photon density. However LEDs – especially many commercial fixtures on the market – have much higher levels of blue photons than HPS, and there can also be large differences in spectra between individual LEDs.

Remember, a 400nm blue photon carries 50% more energy than a 600nm red photon. That means 400 PPFD of blue carries the same energy as 600 PPFD of red.

There are also "hidden" photons that include UVA and Far Red, because these are either not measured by many PAR meters, or they are not counted towards PAR (and PPFD) in the 400-700nm range.

I run my lights around 800-900 PPFD at the top of the canopy, but you can add another 100+ PPFD to that figure if you count the 10% Far Red and 1% UVA.

A higher percentage of blue light for the same PPFD will have more potential to stress plants. The photo-oxidative damage sometimes seen under high amounts of red light is due to chloroplast saturation, so that is a slightly different cause and effect.

 

[Prawn Connery]

In my experience with the strains I run I get these results, that are backed up by what bugbee says.

You’re right, I start seeing light stress around 700ppfd without co2. However I still get yield increases up to around 1000ppfd without co2.

The best looking plants don’t always produce the best results.

Probably because you are delivering more light to the lower canopy where it is the ideal intensity. It sounds obvious, but plant canopies are 3D, not 2D. Which is why side and under-canopy lighting can make such a difference to yield.

 

[Deleted user 90433]

In my experience with the strains I run I get these results, that are backed up by what bugbee says.

You’re right, I start seeing light stress around 700ppfd without co2. However I still get yield increases up to around 1000ppfd without co2.

The best looking plants don’t always produce the best results.

Only c02 I use are mushroom bags so I can't go really expect much higher without bottled c02

 

[Ca++]

Growers forget that not all PPFD is the same.


Remember, a 400nm blue photon carries 50% more energy than a 600nm red photon. That means 400 PPFD of blue carries the same energy as 600 PPFD of red.

PPFD isn't a count of photons. It is the energy.
PPFD is a measure of energy, using energy units such as Watts or Joules.
Changing colour doesn't effect the energy present. The energy present is 400 or 600. What changes, is the photon count. To reach the same PPFD, it takes less blues than reds.

 

[Rocket Soul]

PPFD isn't a count of photons. It is the energy.
PPFD is a measure of energy, using energy units such as Watts or Joules.
Changing colour doesn't effect the energy present. The energy present is 400 or 600. What changes, is the photon count. To reach the same PPFD, it takes less blues than reds.

I dont wanna go ten rounds on this but simply stated that is not correct.

Ppfd: “the number of photosynthetically active photons that fall on a given surface each second”

One blue photon indeed carries more energy than a red. Wavelength and energy per photon is proportional.

Ppfd is measured in umols/m/s; how many photons land on a certain area per second. Umol is a plain number, not a measure of energy.

Look up the definition on google if you like.

All the best and respectfully

 

[Ca++]

I dont wanna go ten rounds on this but simply stated that is not correct.

Ppfd: “the number of photosynthetically active photons that fall on a given surface each second”

One blue photon indeed carries more energy than a red. Wavelength and energy per photon is proportional.

Ppfd is measured in umols/m/s; how many photons land on a certain area per second. Umol is a plain number, not a measure of energy.

Look up the definition on google if you like.

All the best and respectfully

You are not wrong. Which is quite embarrassing, and deserves a long post to explain how I got out the wrong side of the bed. But.. Oh well

 

[Brother Nature]

I've recently been running the same clones under a 1m sq CMH (320w, 3000k) setup and a 1.2m sq LED (640w, 3500k, 5000k, IR), same feed. Clones are Sour Diesel, Phantom Cookies crosses, and some back domina crosses.

So far the CMH plants are actually doing better in most aspects, as much as I hate to say it. Resin production does look better with LED, as does the bud density, but that makes sense using twice the wattage. The CMH plants do have better internodal spacing, are filling out better, have a much happier green look to them, and even smell better.

The enviromental factors are pretty much the same in each tent, with the CMH being slightly less humid and slightly hotter.

I'm really interested to see the smoke results of the test, I will try to post photos when I have the ability.

I've run the SD under LED's and outside before and its a great smoke with both methods, the outdoor being the preffered method, but both poducing stellar results.

I don't feel the difference is going to be something your average consumer will notice, but I do bet there's going to be a noticeable difference in the end product for those of us who do notice the sublities in our final product.

 

[Prawn Connery]

PPFD isn't a count of photons. It is the energy.
PPFD is a measure of energy, using energy units such as Watts or Joules.
Changing colour doesn't effect the energy present. The energy present is 400 or 600. What changes, is the photon count. To reach the same PPFD, it takes less blues than reds.

Where on earth did you get that idea?

I mean, it's in the name!

PPFD = Photosynthetic PHOTON Flux density.

Ie: The density of photons in the 400-700nm range that fall on 1m2 each second

Specifically measured in umol (micromoles) of photons!

EDIT: OK, Rocket beat me to it. At least you now agree with us. Fair enough.

 

[CharlesU Farley]

I dont wanna go ten rounds on this but simply stated that is not correct.

Ppfd: “the number of photosynthetically active photons that fall on a given surface each second”

One blue photon indeed carries more energy than a red. Wavelength and energy per photon is proportional.

As Fonzie on the US television sitcom Happy Days in the '80s used to say, correctamundo!

All the best and respectfully

I almost always learn something from reading your posts, thank you.

 

[Marz]

“It's about self empowerment. That's the wonderful thing about selling seeds. Putting good genetics into the hands of the common man created a shift in power away from organised crime. Once you had something good, you didn't really need anyone else.”​

​

Nevil​

Good quote Sir!!

 

[Kimes]

I tend to push even the seedlings with strong dose of light from the beginning with no ill effects.

in comparison, was bright blue skies today, metered with my photon gadget the spring sun is abt 6000K and 1000ish ppfd.. any and all plants outside easily flourish with that without extra co2.. As the temps rise the world just explodes to green everywhere in a few weeks time.

with high power leds i find little extra temps and nutes to be beneficial. Only time with issues with leds were with coconut coir. Not so much with MH or HPS.

Still learning so I might be full of it though..

 

[Rocket Soul]

You are not wrong. Which is quite embarrassing, and deserves a long post to explain how I got out the wrong side of the bed. But.. Oh well

All good, its refreshing to see anyone here or online reacting well, much love and props

 

[CharlesU Farley]

Good quote Sir!!

I thought the Albert Einstein quote I used to use was insightful, till I read that one fron Nevil down in the Rabbit Hole.

 

[greyfader]

i just thought i would throw in a comment about photon energy. in the pic below i was in the middle of changing out the bulbs on these two plants. one was still all 5000k and one was 2700k with incandescent.

i have a par meter and it showed that i lost approx 50 ppfd at the change-over to 2700k from 5000k.

this is without changing height.