I've read recently that "praying leaves" are actually a sign of plant stress, and not an optimal amount of light.
Jon's First New Digs Grow
- Thread starter Jon
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I start my seedlings into 20-22k LUX. Some could probably even take more than that. I don’t have stretch problems and I don’t kill seedlings but still people have a real problem believing that they want more light to start. Autos especially …no time to waste with stretch and recovery. As far as praying, in my plants I attribute that to vigorous growth and correct moisture in the soil more than anything.
People have ways, and they don’t like to change them.
People have ways, and they don’t like to change them.
That's one of the theories, that it's a way for the plant to prevent light from hitting the leaves.
In its more extreme versions it is commonly acknowledged as too much light.
They do look happy when they are at a praying angle though.
Northward
Well-Known Member
I believe more often than not that the plant is happy imoIn its more extreme versions it is commonly acknowledged as too much light.
They do look happy when they are at a praying angle though.
Gee64
Well-Known Member
The praying is called leaf turgor, turgor pressure, or turgidity. It is the amount of water pressure in the plant cells at any given time. Stomata play a huge part in it's regulation as they control transpiration.
It's a floating target so you can easily and honestly say adding light makes them pray more, but you can also easily and honestly say adding light will reduce turgidity. Thats because both are true.
It's a really complicated process as the state of water availability at the roots, air temp, RH, par, available minerals, they all come into play, and it's a physical reaction, so sometimes it occurs as a good thing and sometimes it's a bad thing. Mostly it's good.
Turgor pressure inside a plant's cell is incredibly strong when fully maxxed, it can drive a root tip thru ashphalt. It's not just in the leaves, it's throughout the entire plant. It's what makes a plant erect. It forces growth.
Problems arise when minerals get out of balance and the plant can't control it's own turgidity, which it mainly does with stomata, and a cold turgid plant expanding in the morning sun can actually rupture cells if a plant can't control it's stomata properly. Or a plant that can't raise it's turgor to a minimum standard won't grow very fast at all.
If you google "what causes turgidity" or "how can you manipulate turgidity" or "what makes a plant turgid" or " does photosynthesis effect turgor pressure" you will get all sorts of stuff on it but it will all contradict itself a bit too.
This is because the plant gets to control it. Some plants will dump all pressure simply by being touched.
So you need to narrow it down to how do healthy plants use turgor pressure. When a plant has perfect light, air, and water it will maximize it's internal turgidity to force root growth, shoot growth, and most importantly flower/seed bracht growth.
There is no "one answer fits all" when it comes to turgidity and/or what causes it because adding any 1 missing element can cause turgidity to rise, but add something the plant doesn't like and it will open stomata wide to drop pressure and slow down.
For the most part a turgid plant is a happy plant. If it's really praying hard and it's healthy, it's praying that hard because it can. You have it dialed for growth.
Here's the slippery slope.... It obviously requires water, but over watering is a stress that makes a plant unhappy so it will dump it's turgidity.
It's a huge rabbit hole. You can't just google up an answer, you need to learn how and why plants do what they do at a cellular level and then turgor pressure will make sense. It's a culmination of all processes. Calcium and potassium are vital for good turgidity.
Just look at it as a good thing and keep doing what you are doing. Push it if you like, but over do 1 thing and it will stop quickly, so enjoy it when it's there and try to keep her in that zone.
It's a floating target so you can easily and honestly say adding light makes them pray more, but you can also easily and honestly say adding light will reduce turgidity. Thats because both are true.
It's a really complicated process as the state of water availability at the roots, air temp, RH, par, available minerals, they all come into play, and it's a physical reaction, so sometimes it occurs as a good thing and sometimes it's a bad thing. Mostly it's good.
Turgor pressure inside a plant's cell is incredibly strong when fully maxxed, it can drive a root tip thru ashphalt. It's not just in the leaves, it's throughout the entire plant. It's what makes a plant erect. It forces growth.
Problems arise when minerals get out of balance and the plant can't control it's own turgidity, which it mainly does with stomata, and a cold turgid plant expanding in the morning sun can actually rupture cells if a plant can't control it's stomata properly. Or a plant that can't raise it's turgor to a minimum standard won't grow very fast at all.
If you google "what causes turgidity" or "how can you manipulate turgidity" or "what makes a plant turgid" or " does photosynthesis effect turgor pressure" you will get all sorts of stuff on it but it will all contradict itself a bit too.
This is because the plant gets to control it. Some plants will dump all pressure simply by being touched.
So you need to narrow it down to how do healthy plants use turgor pressure. When a plant has perfect light, air, and water it will maximize it's internal turgidity to force root growth, shoot growth, and most importantly flower/seed bracht growth.
There is no "one answer fits all" when it comes to turgidity and/or what causes it because adding any 1 missing element can cause turgidity to rise, but add something the plant doesn't like and it will open stomata wide to drop pressure and slow down.
For the most part a turgid plant is a happy plant. If it's really praying hard and it's healthy, it's praying that hard because it can. You have it dialed for growth.
Here's the slippery slope.... It obviously requires water, but over watering is a stress that makes a plant unhappy so it will dump it's turgidity.
It's a huge rabbit hole. You can't just google up an answer, you need to learn how and why plants do what they do at a cellular level and then turgor pressure will make sense. It's a culmination of all processes. Calcium and potassium are vital for good turgidity.
Just look at it as a good thing and keep doing what you are doing. Push it if you like, but over do 1 thing and it will stop quickly, so enjoy it when it's there and try to keep her in that zone.
I've been watching Jon read turgidness for a while. You read your leaf temps vs room temps. I think that's related? Myself...it's tough for me to see changes that come slowly. I'm working on it. @Emilya Green has the gift to notice these minute messages too.
Gee64
Well-Known Member
I actually try to avoid it until stretch is over as sativas just get too darn tall if you push them.
Nine Toed Hippie
Well-Known Member
Total Bullshit.Saturday and the playoffs begin today for us and I am already jonesing for 4 pm. But I had a weird dream last night I was thinking about, and while I’ll keep that in the bank, it did lead to what may (or may not, you guys tell me) be a valid experiment. Anyone who wishes to chime in on this, as always, please do, as this is admittedly off the cuff.
So….
Probably the most often asked questions I get are about what light level to begin seedlings at. My stance on that is pretty well known among those who know me, but in short I tend to be more aggressive than many prefer to begin. This means I usually start them between 500-600 ppfd. For many that would be considered too high.
We can discuss the why I do that later if anyone is curious, but the short answer is that it tends to eliminate stretchy seedlings. Stretchy seedlings is an exceedingly common problem among growers of all skill levels. And especially in the case of autos, it can cost you days of growth that you really really want if you grow autos. In my world the same is true for photos, but it matters in auto growing a lot more, since it ain’t you controlling the veg days with autos. Every day the plant uses its energy to stretch upwards, it is NOT applying the right amount of energy to leaf development. Plants don’t take off usually until they have enough mass of solar panel to fuel the growth, at least in my observation/experience. So you can see why this is especially an issue in the auto growing game. Also in short, I blame the internet.
So back to the light levels to start. I think this might be a valid experiment and I will try this myself in the spring.
Pop any seedling you want. Auto or photo. Put it in your medium, even just a Solo cup would be fine for this. Set your light level (measured with some form of app or whatever, so that when they break ground you know exactly what the ppfd is they are busting into) at whatever level you believe they should start at. Some go as low as 200 ppfd. An often quoted range is 200-400. So set the light anywhere you feel works. Now watch what happens when the plant breaks ground. I will argue all day that if you begin at 200 ppfd, 99 out of 100 times your plant will begin to stretch. This is an experiment. Let it stretch. Watch each day carefully and see when it STOPS stretching. This is easily observable.
Now measure the ppfd at that height.
I am suggesting here that whatever that number is, it represents where that strain, in your medium and feeding and environment and however you grow, would prefer you to begin the light level. I will further argue that it will almost always be a significantly higher number than you would have been comfortable starting at.
There’s my Saturday morning foray into the unknown. Is this a valid experiment based on legit logic? Or total bullshit? All opinions are welcome. If I knew I’d likely say so in some fashion.
NTH
Are you suggesting erroneous nomenclature or etymological inaccuracies?
Surely not the perpetration terminological inexactitudes? lol
Hehe, good to see ya around NTH
- Thread starter
- #71
Hey Shed, speak of the devil. Thanks for the input. I agree with you, there’s a definite difference between equal lux between the sun and LED. Otherwise I’d run them at 1200 start to finish. I’ve searched and asked for the why to this but don’t feel I have an adequate answer just yet. And to be clear, I would never recommend starting a seedling at HIGHER than I go. Cuz exactly what you said will happen. You’ll fry it.
Regarding leaf angle and praying, in my experience I’d say the “maxim to some” that a 45 degree prayer angle is a good signal that you’re at the plants preferred light level is strain specific. Not nearly common enough to be factual as far as I can tell so far. Again we agree. Since in your method you’re in and out, do you ever notice a difference in prayer angle between the two environments in the same day? My outdoor plants prayed way hard a few years ago, way more than 45, almost the whole time. Which is completely anti the 45 degree “theory.” That said, it’s ONE potential indicator.
Vpd is probably the most solid gauge I can find so far, as much as I’ve resisted learning it in detail. Lol. Wonder who hipped me to that? Oh yeah, you.
But that also said, I feel nowadays like if I do everything by observation and experience and reading the plant, and I get that plant to where I believe is firing on all cylinders, the result is almost always that I’m pretty close to prime vpd territory. I have a silly thing where I’d like to only use two measuring tools the light measuring device or app, and my trusty $10 stick moisture meter. Anything I can measure by eye I want to. To me, that’s reading the plant. Like they used to have to with all plants back in the olden days. Lmao.Thanks for chiming in again.
- Thread starter
- #72
Thank you! Now complete it and tell us why. Surely you got more than “Total Bullshit,” yes?
- Thread starter
- #73
Excellent wordsmithing.Are you suggesting erroneous nomenclature or etymological inaccuracies?
Surely not the perpetration terminological inexactitudes? lol
Hehe, good to see ya around NTH
I've never had plants pray in the sun if that's useful, but Gee's explanation is much more scientific, (if making it harder to pin down the specific "why" on any given day).
- Thread starter
- #75
Whoa. Mucho gracias @Gee64. Now we’re talking.
- Thread starter
- #76
Yeah that’s the rub with organics. You gotta know a ton of stuff and everything has to be in concert in order to max potential. It’s way not easy for me. But a challenge.
- Thread starter
- #77
Lol! Thanks @StoneOtter! I’m glad you’ve seen that cuz I had no idea or awareness that that’s what I was doing. All I really know is I can tell when a plant is truly happy and I try to keep em that way.
