LED and BUD QUALITY

[LndRcLvr]

This was grown under a 480w LED from start to finish.

 

[Prawn Connery]

I've had issues with yellow plants and such post transplant plenty, in coco perlite, in sealed rooms under LEDs and working out the dynamic has been fun. But once you do...

The LEDs make less heat or infrared, even when you have red bars in like I do. But the light is clean and bright and even, even if ppfd is not high..I find they have higher food requirements, but the conditions that drive drinking and hence feeding are less, lower leaf temps and less transpiration. So the nutrient uptake less but demands higher. I find then that any sodium still left in the coir can and will cause trouble as the fresh coir is busy loading up on all the other cations and none left for the transplant, and also I find runoff EC's lower than feed EC showing me plants hungry and they look it.

So what I have found works well, is drive them harder from transplant, higher light, higher temperatures and lower RH than optimal VPD for the initial period after transplant. One can get VPD in perfect range for veg sure but im talking about the first take off of the plant, drive it. Feed higher EC as transpiration lower so feed demands relative to water demands are higher, and elevate K and Ca to overcome any sodium left in the media affecting their uptake. I find a calcium and potassium nitrate foliar feed completely in 2 days greens up yellow plants and during the entire time they look like they hate me the roots are amazing and banging out the bottom of the pot white and strong so its not watering nor food recipe, it was just feed strength relative to water given based on water demands being less but feed demands being higher.

But when off the bat higher EC feed given with elevated K and Ca then there is no problem, along with higher temps and lower RH initially..

If you read the documentation from Athena, on LED growing, it says basically first feed after transplant feed at EC 4.0 range in sealed CO2 rooms..thats pretty much it. I don't need to feed that high but feeding high like that initially avoids the issue of the plants looking yellow and underfed prior to establishing themselves.

In the greenhouses I can transplant clones into 40 degree summer heat as I have no choice, and the next day they are lying on the ground and look like death, but im watering them daily already from the second day and by day four they are exploding into life, green as anything and roots are coming out the bottom of the bags already..putting them into such harsh environments but them loving it, in a kushy climate controlled indoor room LED's Co2 dehumidifuers, humidifiers, aircons, perfect VPD, and on same food recipe they will hate me and look like death in 5 days of the perfect environment, go figure...they need a little bit of a push, and a strong feed initially for best results. If ones plants are not infected with shit. If they are, its a whole other chasing your tail endlessly trying to dial shit and work out problems...

This is what I've seen too. I load up my coco right from the start and continually flush it. My seedlings and clones get 2/3 to full strength almost straight away. I run my ECs higher under LED than I ever did under HPS for the same strains. And I load up more on calcium/magnesium nitrates.

 

[Prawn Connery]

Other than overt bleaching, I'm not sure I can even identify light stress. Take a look at this bud shot from yesterday and have at it. Other than a bit of burning on the leaf tips, that are from variations in fertilizer concentration among 20+plants, everything looks normal to me:

View attachment 18988675

I think I was referring to someone else's plant when I said that mate.

 

[CocoNut 420]

I'm in the early stages of flowering with led and using 2.0 ec, I never ever needed anything above 1.4ec with hps.

 

[Rocket Soul]

I'm in the early stages of flowering with led and using 2.0 ec, I never ever needed anything above 1.4ec with hps.

Upping from 1.6 to 2 sorted out a lot of light sensitivity and general lack of plants manning up. At least for us

 

[CharlesU Farley]

I think I was referring to someone else's plant when I said that mate.

Yes you were I was just hoping someone could point out the effect on _buds_. I've seen it on leaves before, but other than bleaching, I just haven't seen any effect of mature buds.

 

[Crooked8]

I'm in the early stages of flowering with led and using 2.0 ec, I never ever needed anything above 1.4ec with hps.

This is truth right here. I was the exact same way with feed.

 

[zachrockbadenof]

lots of interesting points... i'm growing '3' plants in hydro in a 5x5ft tent with a mars fce8000 at 75pct power- i am adding water just about every day, and have tried to bump up the ec to 1.9/2.0, but the plants won't eat it . if i bump it to 2.0 today, when i check tomm the plant is down 1 gallon of water, but the ec is 2.2-2.4- at 1.4-1.6 it stays steady..

 

[malfofa69]

Just get some uvb lights with ur leds n if u really need too just stick hps with it to be sure . But I'm sure uvb will get u glue n terps if u use it right .

 

[Ca++]

This looks like high light to me. Leaves near the top are thick, and failing to expand. Then more leaves grow close by, to have another go. The thick dark leaves are not excess N, but a response aimed at sheltering. Though as I look around, this dark green does have other possibilities today.

A study I just read, fed at 1.8 and a range of light from 200 to 1600. The co2 was 430ppm. Yield increased on a linear scale, all the way.

You're going to make me find it again arn't you..

Cannabis Yield, Potency, and Leaf Photosynthesis Respond Differently to Increasing Light Levels in an Indoor Environment - PMC

Since the recent legalization of medical and recreational use of cannabis (Cannabis sativa) in many regions worldwide, there has been high demand for research to improve yield and quality. With the paucity of scientific literature on the topic, this ...

www.ncbi.nlm.nih.gov

I'm not surprised, except by one thing. That's guppyponics. A most unexpected feed solution for a trial. Though the page is amass with trial quotes, and tbh, I only sifted through it, data mining what I wanted to hear

I don't thing there is a problem with high light early. The problem is switching environment. Typically people change lights, as the plants are moved apart. This makes ppfd matching nonsensical. From lighting the top, to lighting more of it, is more light on the plant. No matter the ppfd reading. Any increase in light, is something the plant needs to adapt to. The pic above has thick leaves that wouldn't work well at 600ppfd. The HPS grows thin leaves, while the blue in LED damages them if you switch over. Giving poor growth until new capable leaves form. A change of light in many directions, can lead to the need for different leaves. It doesn't stop there though.
The answer, as often heard, is go softly softly. Or just put up with some shit growth while they catch up. Today... I can't show you my plants. 3 days ago, they had brix of just 6.5 as I too moved them from A to B. Still LED, but repotted and spaced out. Lower temp and RH. Looked like pic1 from Greyfader. 9 brix yesterday though, and a phantom 20 today. Mostly from a feed increase. They should now be fine. It's not that unusual a progression, though I'm not showing anybody lol

 

[Ca++]

I think the umol calcs looking at 12h 18h or 24h fall apart around 20h. 24h isn't double 12h, because even lights on, the plants will sleep. Dropping their leaves for a few hours, as if lights off. Though you may need a keen eye to spot this, as they won't all be on the same sleep schedule, after weeks or months... hell years of 24h, like some of mine.

Edit: I have not seen this spoke of in forever.

 

[I Care]

I know this is going to be tricky. Two I’ve selected to mature don’t like the LED at all. Looked healthy on 4/21. Now they look like they want to curl the fan leaves down.. Also have a lot of tension built up in the petioles for the fan leaves. Not like it’s drooping, like the petiol is pushing down with possibly more strength then the push up with.

There’s 7 notches in the dimmer on my 250w light. I had I was at least one notch back from full power at 25” and after 36 hours it’s not looking good. So I’m have set the timer straight to a 12 hour break. The light is now around 30”/75cm. The dimmer is set to 4th notch, which should be 50%. All I can do is wait to see if it’s better or worse in 12 hours.

 

[Rocket Soul]

I know this is going to be tricky. Two I’ve selected to mature don’t like the LED at all. Looked healthy on 4/21. Now they look like they want to curl the fan leaves down.. Also have a lot of tension built up in the petioles for the fan leaves. Not like it’s drooping, like the petiol is pushing down with possibly more strength then the push up with.

There’s 7 notches in the dimmer on my 250w light. I had I was at least one notch back from full power at 25” and after 36 hours it’s not looking good. So I’m have set the timer straight to a 12 hour break. The light is now around 30”/75cm. The dimmer is set to 4th notch, which should be 50%. All I can do is wait to see if it’s better or worse in 12 hours.

Is the plant drinking regularly? Sounds like bad transpiration; this is usually cureable by tweaking the environment. What temp/rh do you run? Theres an excellent resource called vpdchart.com

 

[CharlesU Farley]

This looks like high light to me. Leaves near the top are thick, and failing to expand. Then more leaves grow close by, to have another go. The thick dark leaves are not excess N, but a response aimed at sheltering. Though as I look around, this dark green does have other possibilities today.

That's partially my point, along with genetics. The leaves are showing the effect but not the _buds_. I could tell the leaves were stressed myself, because of the way they were folding up into each other, kind of trying to protect themselves from the intense light. But here's the _underside_ of the bud:

Remember, these plants are about 2 to 4 weeks away from harvest and are about 3" below a SF4000. I'll sacrifice a little scorching on the leaves at the very top of the plant for light intensity that penetrates to the very bottom. It's _buds_ I'm concerned with.

Good post, good info. I like your research, isn't applicable to my situation/environment , but solid info!

 

[Ca++]

That's partially my point, along with genetics. The leaves are showing the effect but not the _buds_. I could tell the leaves were stressed myself, because of the way they were folding up into each other, kind of trying to protect themselves from the intense light. But here's the _underside_ of the bud:

View attachment 18992145

Remember, these plants are about 2 to 4 weeks away from harvest and are about 3" below a SF4000. I'll sacrifice a little scorching on the leaves at the very top of the plant for light intensity that penetrates to the very bottom. It's _buds_ I'm concerned with.

Good post, good info. I like your research, isn't applicable to my situation/environment , but solid info!

I think the red comes from high sugar production, without the P to do anything with it. Which is an amount of P, the rest of the plant wouldn't want anyway. So the... Oh I lost the name and I'm late for work... head overload... must find clothes..

 

[CharlesU Farley]

I think the red comes from high sugar production, without the P to do anything with it. Which is an amount of P, the rest of the plant wouldn't want anyway. So the... Oh I lost the name and I'm late for work... head overload... must find clothes..

Damn, sorry you got to go to work! Not to rub it in, but I'm retired now so that's why I've got the time to write all these massive Wall of Words. In addition to the fact that I have very little human interaction for 40+ years outside family/friends and sometimes I have a massive amount of information to disseminate.

My activities yesterday reminded me of the color debate on cannabis. I'll post these and everybody else figure out what they think's happening, all I know is that somehow direct intense light does have an effect of the color on the _same_ plant.

Exhibit A:

Notice the hint of red / yellow on the tops? Here's the underside of that same bud:

Not a whole lot of red / yellow color underneath the leaf material. Nice, dark green. Guess I fucked up because it's not all yellow, so I didn't do the "fade" right.

Seriously, it's my belief the causation of color on cannabis, is as us medical folks say, multifactorial.

And as we all know, the color of cannabis doesn't mean shit when you're actually consuming it.

 

[Rocket Soul]

Damn, sorry you got to go to work! Not to rub it in, but I'm retired now so that's why I've got the time to write all these massive Wall of Words. In addition to the fact that I have very little human interaction for 40+ years outside family/friends and sometimes I have a massive amount of information to disseminate.

My activities yesterday reminded me of the color debate on cannabis. I'll post these and everybody else figure out what they think's happening, all I know is that somehow direct intense light does have an effect of the color on the _same_ plant.

Exhibit A:

View attachment 18992180
Notice the hint of red / yellow on the tops? Here's the underside of that same bud:

View attachment 18992181

Not a whole lot of red / yellow color underneath the leaf material. Nice, dark green. Guess I fucked up because it's not all yellow, so I didn't do the "fade" right.

Seriously, it's my belief the causation of color on cannabis, is as us medical folks say, multifactorial.

And as we all know, the color of cannabis doesn't mean shit when you're actually consuming it.

Pretty sure its multifactorial and to a great extent genetic. But... its also a good idea to look to the generalities of horticulture where this thing has been amply studied. Purple and red is Anthocyanin - a photoprotective photopigment. Its usually caused by high light intensity with not enough heat.
My suggestion to anyone suffering from this is lower light intensity, raise heat, check that the plant is receiving sufficient nutes (you need to make sure youre feeding properly AND make sure your plant is able to transpire properly, for LED: following VPD) and that the water your giving isnt too cold. This is going to clear up 90% of the cases.
Seeing this in the end of a grow is usually fade related: chlorophyll is green and much more visible to the human eye. When you remove green you see yellows and purples; they were already there but not visible when the leaves were full of chlorofyl. all ok and normal. In this case here i think you may have gone over board on light, 3" is very little for that kinda a light.

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.

 

[Hiddenjems]

this smaller nugget is still about 3 weeks from finishing and it was under full spectrum led and I've only got the dimmer set between 600-700 ppfd,anything over that severely burns the plants

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.

 

[maryjaneismyfre]

LOL i used to push over 1000ppfd for years with single ender HPS close to the plants with batwings...with air exchange and get over g/w reliably. With correct air movement pattern and enough air exchange CO2 supplementation only gets good at well over 700ppfd... My fattest buds are the summer crop in the greenhouses as the light at midday is maxing out various meters at 2000 and 3000ppfd respectively. Ambient Co2...

Best looking plants, generally produce the best results, unless buds get so huge that new concerns arise like botritus etc. Healthiest plants under highest light produce the most THC if environment is happy. Our ambient CO2 is close to 500ppm in the day and up over 700ppm at night and if your air at leaf surface is exchanging all the time, its more than enough at high light. That said ...The beauty of LED is in sealed rooms, and sealed rooms one must climate control and provide CO2. High light, elevated CO2, nice food, correct watering, media and genetics and one can pull off the most reliably high quality flower year round in an LED sealed CO2 room for lowest running cost compared to HPS where one has to change bulbs and cool a little more, but much over muchness, once I got the change in food sorted I'm pulling pukka bud out LED rooms, HPS rooms and greenhouses, lit and not lit. The best bud of the year from the unlit summer crop, as low bay greenhouses and sunlight...well no replacement for displacement as DHF used to say.. But you get one shot at that in the year. The high tech high bay lit houses we pull 4 summer crops a year and the indoor it's year round for 6 crops. So, each has its merits or disadvantages, still, once you have them figured out.


Both are same clone, in different environments, both are happy. Above higher light fatter bud, lower CO2 though, below is double the CO2, above double the light. LOL..but both I'm happy with. This below was my second sealed room full climate control crop and my first LED crop. Above was not my first greenhouse crop LOL. I lost count long ago of those..

 

[Douglas.Curtis]

And as we all know, the color of cannabis doesn't mean shit when you're actually consuming it.

I have noticed for decades. Same strain, different grow methods, the lightest colored flowers *always* have more flavor/high and lighter ash weight/color than the darker green flowers. Always.

The darker the green at harvest, the harsher and blacker the smoke and ash will be.