radiant Rudy
Well-Known Member
Thanks for the heads up
Would you please post a citation that connects purple cannabis petioles to irradiance? Ty.
HLG vs. HGL (Perm Edition)
- Thread starter Big Perm
- Start date
Would you please post a citation that connects purple cannabis petioles to irradiance? Ty.
coreywebster
Well-Known Member
Yes it is.
Moflow
Well-Known Member
I'd be interested in the links too.
In my experience, under the Samsung white leds 4000K at the moment - same with 3000K Cree cobs I get red stems whilst same clones outdoors under sunlight the stems stay green.
Similar temperature and feeds.
Indoor
Outdoor
Kushash
Well-Known Member
I went looking for the links. I found two of them in the hlg-vs-hgl-side-by-side thread.
Hope these help. Not sure if the 1st one mentions light stress or not.
post #580
http://landresources.montana.edu/nm/documents/NM9.pdf
Purplish-red discolorations in plant stems and leaves are due to above normal levels of anthocyanin (a purple colored pigment) that can accumulate when plant functions are disrupted or stressed. This symptom can be particularly difficult to diagnose because cool temperatures, disease, drought and even maturation of some plants can also cause anthocyanin to accumulate. Certain plant cultivars may also exhibit this purple coloring.
#693
Anthocyanins are flavonoid compounds that protect plant tissues from many environmental stresses including high light irradiance,
Rocket Soul
Well-Known Member
Look into high irradience response
Not a 100% its covered in this:
OneHitDone
Well-Known Member
There is no way anyone here is running higher lighting levels indoors than @Moflo is giving his outdoor plants.
I have occasionally even seen these symptoms using T5 and HID lighting.
The onset usually comes right after cloning and being in small volumes of grow media for too long. Then it appears to set in either a nutrient imbalance or just some sort of overall unhappiness do to root confinement.
Moving them to a larger container promptly will generally remedy the situation and the new grow will start coming out solid green almost immediately. If left in an unhappy purple stemmed state for too long it can end up taking a long time, even months to grow out of it.
It is an unpopular statement but it is my opinion that led's being an incomplete and in most cases wonky spectrum and especially lacking in Infrared radiation are a direct contributor to these issues. Some can work around it but it's like throwing a stick in the spokes of your own bicycle
I have occasionally even seen these symptoms using T5 and HID lighting.
The onset usually comes right after cloning and being in small volumes of grow media for too long. Then it appears to set in either a nutrient imbalance or just some sort of overall unhappiness do to root confinement.
Moving them to a larger container promptly will generally remedy the situation and the new grow will start coming out solid green almost immediately. If left in an unhappy purple stemmed state for too long it can end up taking a long time, even months to grow out of it.
It is an unpopular statement but it is my opinion that led's being an incomplete and in most cases wonky spectrum and especially lacking in Infrared radiation are a direct contributor to these issues. Some can work around it but it's like throwing a stick in the spokes of your own bicycle
radiant Rudy
Well-Known Member
I'm close to 675 w in a 2 x 4. When irradiance issues present in my grow the symptoms are contorted leaves, bleaching and retarded growth. With luxury levels of P purpling of stems and petioles is not observed.
hybridway2
Amare Shill
I'd be interested in seeing them. Thnx!
Moflow
Well-Known Member
Light levels outdoors this year have been very low, loads of cloud and rain, so there will be plenty of folks giving their plants higher light levels.
All my outdoor plants have suffered with poor growth this year.
Moflow
Well-Known Member
Light levels outdoors this year have been very low, loads of cloud and rain, so there will be plenty of folks giving their plants higher light levels.
All my outdoor plants have suffered with poor growth this year.
radiant Rudy
Well-Known Member
Yes, very interesting. In my experience the nutritional needs indoors, under high irradiance, 3-4k cobs would not be well met by using a feeding program that is effective for outdoor plants. I think differences in photo respiration vs photosynthesis, that result from cooler leaf temps but high irradiance under led, effects the transport of minerals and other metabolites.
Under LED I think there is almost no such thing as too much calcium. Using high irradiance LED, calcium deficiency had been a chronic problemin my garden. Maybe the same is true for P. If less P is being transported because the leafs are cooler then more P must be available to the roots to compensate for less P transport through respiration. Also similar with Mg but Mg is a far simpler fix than Ca or P.
Since i stopped using P amendments and deployed PSB I havent seen a purple petiole indoor or out in many grows,
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pulpoinspace
Well-Known Member
I used to veg under four 4000k cobs, dimmed from 100-200w in a 4'x2'. usually 18"-20" from my plants. it was not uncommon for me to find 3-finger or 1-finger leaves, red or even dark purple petioles and drooping growth during mid veg.
I have since switched to 200w of HOT5 and all other factors unchanged (same strain, nutrients, climate, etc.) Since then I have not seen a single 1 or 3-finger leaf. My petioles are green with a light pink tint, and everything grows much happier.
I don't think "LED deficiency" is a thing, but my plants were unhappy under the LED for some reason. In other words, I was doing something wrong, not the LEDs. Conventional wisdom and these forums had me trying epsom salt and moving the lights further and further away. For whatever reason my veg plants just never stayed happy the way they do under 6400k flouros.
I read a blog on HLG's website years back about how high CCT white LEDs don't have the same benefit for plants because of the spectral distribution. The spikes that make up 6400k flouro spectrum for whatever reason plants love it in veg. I don't think that article is up anymore though.
I have since switched to 200w of HOT5 and all other factors unchanged (same strain, nutrients, climate, etc.) Since then I have not seen a single 1 or 3-finger leaf. My petioles are green with a light pink tint, and everything grows much happier.
I don't think "LED deficiency" is a thing, but my plants were unhappy under the LED for some reason. In other words, I was doing something wrong, not the LEDs. Conventional wisdom and these forums had me trying epsom salt and moving the lights further and further away. For whatever reason my veg plants just never stayed happy the way they do under 6400k flouros.
I read a blog on HLG's website years back about how high CCT white LEDs don't have the same benefit for plants because of the spectral distribution. The spikes that make up 6400k flouro spectrum for whatever reason plants love it in veg. I don't think that article is up anymore though.
salmonetin
Well-Known Member
please ...im too curious about these SPDs ...any SPD of your HOT5 and cobs?...brand?...model?.... thanks in advance...
Si Wilson en exterior lo vi pasar por frio ...sobretodo con noches frias...en interior si las condiciones climaticas eran las mismas me gustaria comparar esos spd solo por curiosidad...
paz
Saludos
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Moflow
Well-Known Member
quien es wilson?
pulpoinspace
Well-Known Member
I used bridgelux vero29 4000k (the purple line):
now i use agromax 6400k t5:
i really wish i could find that old blog post from HLG but i cannot.
hybridway2
Amare Shill
The WavePoint - Ultra Growth Wave too right?
pulpoinspace
Well-Known Member
I haven't used those I just use regular old 6400k cool white
Barristan Whitebeard
Well-Known Member
Here you go sir.
High CCT fluorescent/T5 VS LED Spectrum 4000K 5000K 6500K
Higher CCT fluorescent/T5 like 5000K and 6500K work great for greens and clones. However Higher CCT LED have a very different spectrum and may not perform as well Higher CCT fluorescent/T5. Charts below show the standard 80 CRI spectrum for Samsung 561C LED. We recommend 4000K and 5000K for...
horticulturelightinggroup.com
Is this the post you were looking for?
pulpoinspace
Well-Known Member
there ya go. thanks @Barristan Whitebeard yeah i remembered it having more info than that. not really much there but it does illustrate how different the spectrums are for led and flouros.