longball
'21, '23 COE Winner
Do these humidity and temp thresholds fall within your standard VPD chart range or is/should there be a separate VPD chart for LED?
Longball.
LED tutorial forum
- Thread starter BrotherBoris
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Do these humidity and temp thresholds fall within your standard VPD chart range or is/should there be a separate VPD chart for LED?
Longball.
Freedom_Fighter
Well-known member
As far as relative humidity is concerned, and how it affects plant transpiration, if the grow space is too humid, the plant can't transpire correctly, or optimally. The vapor in the air applies pressure upon the leaf surface, and if the pressure is greater than the water pressure built-up inside the leaf, the plant is unable to transpire, or release the build-up into the air. The pressure inside the leaf must be greater than the vapor pressure in the air, in order for it to be released.
When the plant can't transpire, it won't drink water. When it doesn't drink, no calcium will be moved up through the plant, into the leaves; or at least not at optimal levels. Even if there is sufficient calcium present in the grow medium, it cannot be accessed if the plant isn't drinking, due to excessive humidity (air vapor pressure).
Calcium is the main messaging molecule and is involved in all the major growth processes. If it's being locked out due to high humidity, it affects everything. High powered LED lights can cause the plant to consume phosphorus a lot faster, resulting in reddish / purple stem discoloration.
I am, by no stretch of imagination, an expert in this area. I'm merely sharing a few observations that I've made, in the past. In terms of growing experience, I concede to Charles. Yes, I got started early but haven't grown continuously for 40 years; and certainly cannot claim to have grown "thousands" of plants.
Cheers! - FF
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dankd
Well-known member
so there is also an upper limit then ok i didn't realize. it seems most of the problems are from too low humidity/temp than too high though
i wish i saved the picture someone posted on a forum of the instructions from their led manufacturer saying the plants would need an increase in calmag i think(?)
i didn't get to the science of vpd i just know when the fall sets in the plants are kaput. switch to hid and pristine health. for pristine health under led i need to wait until spring and summer
edit: because, only at that time is the weather guaranteed never to go to cold/low humidity. it seems with led even a dip into those ranges can be too much
i wish i saved the picture someone posted on a forum of the instructions from their led manufacturer saying the plants would need an increase in calmag i think(?)
i didn't get to the science of vpd i just know when the fall sets in the plants are kaput. switch to hid and pristine health. for pristine health under led i need to wait until spring and summer
edit: because, only at that time is the weather guaranteed never to go to cold/low humidity. it seems with led even a dip into those ranges can be too much
Swifty
'23, '24 COE Winner
I did not document then Growviper, so unfortunatly no pictures.
It was a horrible experience, I switched back after a couple of weeks to my CMH and after 2-3 days I saw new growth and finished with the CMH.
Problems started to get real bad after switching to 12/12.
I appreciate your feedback @dankd, @GrowViper, @Freedom_Fighter.
Thank you.
charlesufarley
Well-known member
I'm working on a long post for another forum that I'll cross post in here regarding indoor lighting history and the lights that I've used. I've been using LEDs for over 10 years now and absolutely love them.
To give you an idea how far I've come, I used to use this to illuminate a 2x5 grow closet. It's a 1 kilowatt MH fixture, with a Sunmaster warm deluxe bulb, purchased in 1987:
It has been my experience, monitoring forums over many years, that when people make the transition from MH/HPS to LED, it's the temp and humidity alterations that are the biggest challenge, not a change in the fertilizer needs.
Freedom_Fighter
Well-known member
HPS Vs CMH Vs LED | Should you upgrade from HPS and MH? || MIGRO
Here's an interesting video that appeared in my YouTube stream today. It's a fair comparison, I think, though a little dated, being 3 years old now. I don't expect HPS / HID lighting to fade away any time soon, but to evolve.
As far as HID tech goes, though, I think plasma lights are its future. It's amazing and currently the only light tech with the potential to give LED tech a real challenge in the future, if manufacturers can ever lower their cost. Currently they're way too expensive for hobby home growers; and only a thing for large scale commercial grows.
The best UVB light I've ever seen is Plasma HID. MIGRO has a review video on that, but it's only for commercial operations.
Cheers! - FF
LED vs HPS in 2021 | 600W HPS to LED comparison | MIGRO (04•16•21)
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ZenC
Active member
I do not really want to promote any manufacturer but when youre in the EU this is a very good site/seller. He makes everything himself and you can ask him anything. His light is top notch but you have to build it yourself, not that hard tho. You can vary with alot of different spectra and dimm whatever you want separately.
cre.science
Crescience | LED Pflanzenlampen & Indoor Garten Controller
Unsere hocheffizienten LEDs und Lösungen für Indoor Garten Automatisierung sind so einzigartig wie die Anforderungen unserer Kunden. Jetzt Crescience entdecken!
cre.science
CanaViper
Well-known member
Love the micro guy. Good test methology, good research, good execution, excellent reviews. Plus he seems fair when reviewing the competition too. Solid analysis and advice
IMHO
/steve
Freedom_Fighter
Well-known member
LED vs HPS || Old School Growing
dankd
Well-known member
just sharing the new episode from grow under the stairs, one of the best youtube cannabis growers who uses led. this is a post harvest episode where he compares 12 strains
The Grow Under The Stairs
The Grow Under The Stairs
Freedom_Fighter
Well-known member
Mmmmnice!
Member
Vapor Pressure Deficit VPD Calculator - Dimlux Lighting - The Best Grow Lights
Vapor Pressure DeficitCalculator Calculate both Room VPD and Leaf VPD automatically Just enter the value below to generate the VPD values for your room and your plants. You’ll need to know the room’s temperature, relative humidity, and the plant’s temperature. We recommend calibrating your...
www.dimluxlighting.com
VPD calculator for those that might need it...
Hi all. I have some long and boring questions regarding various lighting options - sorry if I'm unclear but I'll try my best.
Essentially, my experiences with the various lighting options are very different to most of what I see people saying on the internet, and I am wondering why is this, and does anyone else feel similar to me?
TLDR; I find that overall HPS is _absolutely untouchable_ in nearly all respect - does anyone else feel the same?
Long version is something like this:
I have found that "blue-leaning" like the Mars TS1000 LED lighting fixtures produce growth that is far too leafy, and the resin on dried flowers is too clear and "sandy/gritty"- buds just simply aren't "juicy" like they should be. Also, some individual plants are reluctant to kick into flowering properly and take longer than they should. Perhaps the biggest issue with this type of LED is that the humidity needs to be up at about 80-85% otherwise things just aren't "happy". This exacerbates the tendency towards very leafy growth, and is not practical during flowering because of mold risks.
Under "red-leaning" LED fixtures like the Mars TS600, I have found things to be somewhat better, with more even growth pattern, reasonably dense buds and "silky" resin, but the plants either always smell "stressed" because the light is too close, or just don't perform as they should because the light is too far. Lower leaves and buds that are "fluffy popcorn" under HPS tend to be smokeable, but this doesn't translate to a better overall yield.
Under "red-leaning" 930 CMH I have found that plants stretch in a similar manner to HPS, but they just don't fill out and put on weight like an HPS, although they do produce nice sparkly resin, and plants ripen a few days quicker than HPS. People say that the yield on a 315W CMH is superior to a 400W HPS, but I have not found this at all. Not, at, all.
Under "blue-leaning" 942 CMH the plant structure is pretty good. Resin production is pretty good. In fact, everything is pretty good - but just nowhere near as good as a 400W dual-spectrum HPS.
Under dual-spectrum HPS, plant structure is what we want to see, plants smell "happy" and not stressed, resin is great and buds are much "juicier" than under LED and much fatter than under CMH. In fact, everything about the HPS growing experience is just head-and-shoulders better than the other options. Even the heat isn't that much of an issue if you are able to vent outside.
However, opinion on the hyper-global-omni-meganet appears to be "HPS is dead grandad, LED yields at least 3 metric tonnes per Watt, CMH is kinda OK but LED is king". All the while I'm sat here thinking "That just doesn't make sense to me".
Has anyone else had similar experiences? What might I be doing wrong?
The following is not my picture, but it illustrates my point - I can achieve resin like this under HPS but never going to happen under LED.
Thanks for reading! Take care all.
Essentially, my experiences with the various lighting options are very different to most of what I see people saying on the internet, and I am wondering why is this, and does anyone else feel similar to me?
TLDR; I find that overall HPS is _absolutely untouchable_ in nearly all respect - does anyone else feel the same?
Long version is something like this:
I have found that "blue-leaning" like the Mars TS1000 LED lighting fixtures produce growth that is far too leafy, and the resin on dried flowers is too clear and "sandy/gritty"- buds just simply aren't "juicy" like they should be. Also, some individual plants are reluctant to kick into flowering properly and take longer than they should. Perhaps the biggest issue with this type of LED is that the humidity needs to be up at about 80-85% otherwise things just aren't "happy". This exacerbates the tendency towards very leafy growth, and is not practical during flowering because of mold risks.
Under "red-leaning" LED fixtures like the Mars TS600, I have found things to be somewhat better, with more even growth pattern, reasonably dense buds and "silky" resin, but the plants either always smell "stressed" because the light is too close, or just don't perform as they should because the light is too far. Lower leaves and buds that are "fluffy popcorn" under HPS tend to be smokeable, but this doesn't translate to a better overall yield.
Under "red-leaning" 930 CMH I have found that plants stretch in a similar manner to HPS, but they just don't fill out and put on weight like an HPS, although they do produce nice sparkly resin, and plants ripen a few days quicker than HPS. People say that the yield on a 315W CMH is superior to a 400W HPS, but I have not found this at all. Not, at, all.
Under "blue-leaning" 942 CMH the plant structure is pretty good. Resin production is pretty good. In fact, everything is pretty good - but just nowhere near as good as a 400W dual-spectrum HPS.
Under dual-spectrum HPS, plant structure is what we want to see, plants smell "happy" and not stressed, resin is great and buds are much "juicier" than under LED and much fatter than under CMH. In fact, everything about the HPS growing experience is just head-and-shoulders better than the other options. Even the heat isn't that much of an issue if you are able to vent outside.
However, opinion on the hyper-global-omni-meganet appears to be "HPS is dead grandad, LED yields at least 3 metric tonnes per Watt, CMH is kinda OK but LED is king". All the while I'm sat here thinking "That just doesn't make sense to me".
Has anyone else had similar experiences? What might I be doing wrong?
The following is not my picture, but it illustrates my point - I can achieve resin like this under HPS but never going to happen under LED.
Thanks for reading! Take care all.
Skunkerbudz
2022 COE Winner
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Led is the way you cant beat them in any field is just harder to Tune in. Also depends what leds used and feed .
thaseus92
Active member
I dont know which LED u all use but my 240w lamp from this year beats easily all 400w mh/ndl lamps i got so far even the greenmaster that was in my opinion one of the best ndl u could get these days 10 years ago.
resin production isnt lower in any way, trichomes got the same size rated by chatching them with the same size bubblebag, the only thing i would rate a litte worster is the last swelling of the buds in the last 3 weeks of blooming cycle.
Guess the ndl had a heavier focus on red and this gave some extra boost that the led cant give. but therefore i had to switch the ndl to mh for growing cycle what my led easy covers.
What i so far can say is my newest LED raised the nutrient need by i guess 10-20% within the same strain compared to the last LED used before.
But to be fair the LED prior to this only used 150w on 2 single COBs and the new one comes with over 2 led per square cenitmeter so i guess a lot more light hits the plant and therefore more nutrients are needed.
So for german/europe people in this forum i really can recommend this little game changer for a sweet price. I got my for 250€ thats quite fair i guess.
and if someone is fit in electronics they also sell all kinds of LED boards to make your own lamp like you need in size or spectre
resin production isnt lower in any way, trichomes got the same size rated by chatching them with the same size bubblebag, the only thing i would rate a litte worster is the last swelling of the buds in the last 3 weeks of blooming cycle.
Guess the ndl had a heavier focus on red and this gave some extra boost that the led cant give. but therefore i had to switch the ndl to mh for growing cycle what my led easy covers.
What i so far can say is my newest LED raised the nutrient need by i guess 10-20% within the same strain compared to the last LED used before.
But to be fair the LED prior to this only used 150w on 2 single COBs and the new one comes with over 2 led per square cenitmeter so i guess a lot more light hits the plant and therefore more nutrients are needed.
So for german/europe people in this forum i really can recommend this little game changer for a sweet price. I got my for 250€ thats quite fair i guess.
and if someone is fit in electronics they also sell all kinds of LED boards to make your own lamp like you need in size or spectre
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