Thanks for the details.
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passive plant killer
- Thread starter delta9nxs
- Start date
C
Carl Carlson
D9, just to clarify on your version of the defoliation, you are doing the jrosek, which is to remove the fan leaves from the main stem only, or something beyond that?
good morning! i've been doing the half jrosek, which is DF at the end of stretch. he does it again at 45 days. i'm doing the end of stretch only, but radically. every fan leaf with a visible stem is removed.
drip rate in flower before any DF was approx 100-104 per minute. now it is around 60 per minute.
i've just started doing the full k33ftr33z with a clone in veg, so we'll see how it goes.
efficacy of the DF technique is heavily dependent on strain and lighting.
some strains are just not going to react well and a lot of folks just don't have adequate lighting to make much difference.
i have a naturally bushy plant and intense lighting so i'm getting a good response.
later
Did some quick looking around today (yeah, I used the search function) but never really saw a full pic of your flower room layout.
I think you use 6 hortilux HPS total.
Veg is in a circle around 1kW in a 7x7 space.
Flower looks like this:
-0-0-0-0-
X X X X X
-0-0-0-0-
with 5x1kW HPS in cool tubes, open room, direct vent via cool tubes?
That doesn't seem likely, as it puts your room 16 x 8 and I'm pretty sure those aren't your dimensions.
I think you use 6 hortilux HPS total.
Veg is in a circle around 1kW in a 7x7 space.
Flower looks like this:
-0-0-0-0-
X X X X X
-0-0-0-0-
with 5x1kW HPS in cool tubes, open room, direct vent via cool tubes?
That doesn't seem likely, as it puts your room 16 x 8 and I'm pretty sure those aren't your dimensions.
the flower room is 6.5' wide and 18.5' long. 120 sq ft. it is impossible for me to get an overall shot of the room. or to even get a complete shot of one plant because of size and proximity.
i vent via cooltubes except for a duct fan at ceiling height scavenging heat off the ceiling. i have an ac/heat duct i installed going into the area split off the house main duct.
5 lights in flower with 2 rows of 4 plants centered between the lights. this puts each plant and 2 lights at the points of an equilateral triangle. the closet parts of each plant are rarely more than 8" from the light. light height is not adjusted. the lights are on 44" centers.
it is very difficult to just move around in there. i had to use cool tubes here to avoid getting burned. you have to touch both plants and lights to move.
i've got an old long sleeve shirt i use in there and it's starting to look like a baseball players batting helmet with all the resin on it. if i sit down the back of the shirt sticks to the chair and comes off like peeling velcro.
as careful as i am i'm still breaking branches. defoliating in veg might allow me a little more room if it doesn't decrease yield.
In this thread by D9: "...tds and ph on lead plant is 617 ppm @ 5.5. i have been feeding 620-630 or so. tomorrow will be 8 weeks with no change.
This change was commented on OldOne's Thread: "...very nice! looks really healthy but just a little bit of tip burn, which is usually, but not always, indicative of over ferting. when i started defoliating in flower i had to drop to ec 1.2 because of similar symptoms. no loss in yield, though."
Additionally, out of this thread: "...drip rate in flower before any DF was approx 100-104 per minute. now it is around 60 per minute."
---
A couple of observations first, then I'll be back for some speculation and hypothesis:
I presume that the drip rate in flower is what has systematically stabilized once all plants started getting the DF treatment; that is, your drip rate didn't drop in half after you plucked just one plant.
You didn't change the nute concentration, and reduced leaf mass... and then observed leaf burning. What's the timeline on this? i.e. does it show burning the next day, or what?
This change was commented on OldOne's Thread: "...very nice! looks really healthy but just a little bit of tip burn, which is usually, but not always, indicative of over ferting. when i started defoliating in flower i had to drop to ec 1.2 because of similar symptoms. no loss in yield, though."
Additionally, out of this thread: "...drip rate in flower before any DF was approx 100-104 per minute. now it is around 60 per minute."
---
A couple of observations first, then I'll be back for some speculation and hypothesis:
I presume that the drip rate in flower is what has systematically stabilized once all plants started getting the DF treatment; that is, your drip rate didn't drop in half after you plucked just one plant.
You didn't change the nute concentration, and reduced leaf mass... and then observed leaf burning. What's the timeline on this? i.e. does it show burning the next day, or what?
So, you've had nute burning on plants at a level that previously didn't result in burns.
You're highest yield to date was a defoliated plant (plucked at the end of stretch). I presume if quality had suffered, you would have discontinued the practice.
Question One:
At one point, the nute concentration was not causing burns, but then it was. Why?
Speculative Answer One: "Efficiency"
Maybe the older leaves are acting as a store house for mobile nutes. What was being stock piled within the old leaves now has no place to 'overflow' and this increased concentration is resulting in leaf burn.
Implications: You've reduced your nute concentration to one half, and reduced your take-up by one half, yet your yield has improved/remained stable. Simple math says that your feeding at ~1/4 the strength you used to, which implies a quadrupled efficiency in nute usage of the plant to maintain yield. Where does this come from?
While the stability of the solution may result from the wick isolation, the root ball analysis you've done suggests that there is a nearly complete food uptake. So we think the ratios are good. If the ratios are good, and they are being provided in a manner that is constantly available to the plant, why would she need to stockpile mobile nutes? That is, she eats exactly what she needs, and grows flowers. (So, in a perfect situation, older leaves aren't necessary).
ASIDE
Who is running Jack's Hydro in a fast moving rDWC... cause this might be a solution to somethe problems that caused me to move away from the system).
So through the defoliation technique, in conjunction with Jacks, your hitting each node of the plant with sufficient building blocks (i.e. CO2 and nutes) with sufficient energy (i.e. direct light) to build flowers directly, WITHOUT-SHADE-LEAVES-ACTING-AS-A-BUFFER.
Speculative Answer Two: "Overdrive"
Some how, the defoliation technique is (hormonally?) stressing the plant to drive it harder, such that there is more transpiration/surface area of the remaining leaf mass. Accordingly, the old nute concentrations are concentrating too much in the new growth, resulting in burns.
You're highest yield to date was a defoliated plant (plucked at the end of stretch). I presume if quality had suffered, you would have discontinued the practice.
Question One:
At one point, the nute concentration was not causing burns, but then it was. Why?
Speculative Answer One: "Efficiency"
Maybe the older leaves are acting as a store house for mobile nutes. What was being stock piled within the old leaves now has no place to 'overflow' and this increased concentration is resulting in leaf burn.
Implications: You've reduced your nute concentration to one half, and reduced your take-up by one half, yet your yield has improved/remained stable. Simple math says that your feeding at ~1/4 the strength you used to, which implies a quadrupled efficiency in nute usage of the plant to maintain yield. Where does this come from?
While the stability of the solution may result from the wick isolation, the root ball analysis you've done suggests that there is a nearly complete food uptake. So we think the ratios are good. If the ratios are good, and they are being provided in a manner that is constantly available to the plant, why would she need to stockpile mobile nutes? That is, she eats exactly what she needs, and grows flowers. (So, in a perfect situation, older leaves aren't necessary).
ASIDE
Who is running Jack's Hydro in a fast moving rDWC... cause this might be a solution to somethe problems that caused me to move away from the system).So through the defoliation technique, in conjunction with Jacks, your hitting each node of the plant with sufficient building blocks (i.e. CO2 and nutes) with sufficient energy (i.e. direct light) to build flowers directly, WITHOUT-SHADE-LEAVES-ACTING-AS-A-BUFFER.
Speculative Answer Two: "Overdrive"
Some how, the defoliation technique is (hormonally?) stressing the plant to drive it harder, such that there is more transpiration/surface area of the remaining leaf mass. Accordingly, the old nute concentrations are concentrating too much in the new growth, resulting in burns.
the drip rate of around 60 per minute was achieved after the first six plants were DF'd. 2 plants at any given time are not DF'd because they are not finished with stretch.
it took most of a week after DF'ing the first plant to show symptoms of overferting. basically consisting of tip and edge burn and hooked leaves. these were bud leaves because everything else was gone. this was around ec 2.0. prior to DF'ing there were no symptoms whatsoever. after DF'ing the plants still grew the bud weight but looked like shit.
since correcting to ec 1.2 the symptoms have disappeared. i'm going to work ec back up a little at a time until i see symptoms and then back it down a little bit.
I can see it a bit... did it effect the final quality?
Work it back up there! (But your biggest girl was great from the very beginning, wasn't she? So maybe dropping the EC to 1.2 can't be blamed for the following girls to be a oz or two lighter.)
I'm not supposed to be here right now, but I'll be back this evening.
Work it back up there! (But your biggest girl was great from the very beginning, wasn't she? So maybe dropping the EC to 1.2 can't be blamed for the following girls to be a oz or two lighter.)
I'm not supposed to be here right now, but I'll be back this evening.
Quotes by ImaginaryFriend
“So, you've had nute burning on plants at a level that previously didn't result in burns.”
yep, the symptoms appeared after DF'ing at the end of stretch.
“You're highest yield to date was a defoliated plant (plucked at the end of stretch). I presume if quality had suffered, you would have discontinued the practice.”
all four of these last plants were DF'd. They produced good quality, potent bud. They really didn't look all that bad, i'm just used to growing plants that have no visible problems.
“Question One:
At one point, the nute concentration was not causing burns, but then it was. Why?”
Good question. I think nitrogen is the culprit. When defoliated at end of stretch I believe nitrogen intake goes way down. The plant is not building much more mass at this point. Root and shoot growth are mostly over.
The fan leaves are like radiators and storehouses. They radiate excess moisture away from the plant via the stomata mechanism and release stored energy for flowering.
I don't think the buds themselves need as much N after stretch. But with fan leaves intact I believe the leaves act as a nutrient buffer for N. With them removed the buffer/control mechanism is gone and the bud formations are forced to handle it alone. In other words I don't think all parts of a plant consume nutrients at the same rate and the bud formations are getting too much N after DF.
this is also supported by my observation that the ph in flower has been running a few points higher in the reservoirs of the DF'd plants than the non-DF'd ones. Remember the discussion above about NO3 driving ph up. With DF we are getting a different consumption rate.
“Speculative Answer One: "Efficiency"
Maybe the older leaves are acting as a store house for mobile nutes. What was being stock piled within the old leaves now has no place to 'overflow' and this increased concentration is resulting in leaf burn.”
I think so.
“Implications: You've reduced your nute concentration to one half, and reduced your take-up by one half, yet your yield has improved/remained stable. Simple math says that your feeding at ~1/4 the strength you used to, which implies a quadrupled efficiency in nute usage of the plant to maintain yield. Where does this come from?”
I mentioned this in the defoliation thread. Cannabis, especially indicas because of where they occur, usually goes through the vegetative stage in the “wet” season and the flowering stage in the “dry” season.
Nutrients are not taken up as readily in drier root conditions. So the nutrient flow for naturally occurring plants is reduced. I think the plant has evolved to store nutrients in advance for this. The fans leaves are the storage bank. With DF we remove the storehouses yet still supply the plant with all the nutrients it can use at any given time.
“While the stability of the solution may result from the wick isolation, the root ball analysis you've done suggests that there is a nearly complete food uptake. So we think the ratios are good. If the ratios are good, and they are being provided in a manner that is constantly available to the plant, why would she need to stockpile mobile nutes? That is, she eats exactly what she needs, and grows flowers. (So, in a perfect situation, older leaves aren't necessary).”
The plant is programmed to stockpile nutrients for flower. The 3-1-4 ratio is great for veg and pre-flower and is good for flower with fan leaves intact.
So with continuous liquid feed fan leaves are not necessary after stretch.
But I do think a correction is called for.
Using the jack's/calcium nitrate combo we have close to a 3-1-4 ratio.
By dropping the dose to ec 1.2 I was able to stop the display.
What I propose to do now is to drop the calcium nitrate altogether in flower and substitute the calcium chloride. As the jack's has 50 ppm NO3 in the base product this would change the ratio to approx a 1-1-4 while letting me bring the overall dose back up to ec 2.1.
if I get burn again i'll back that down until it stops.
“ASIDEWho is running Jack's Hydro in a fast moving rDWC... cause this might be a solution to somethe problems that caused me to move away from the system).
So through the defoliation technique, in conjunction with Jacks, your hitting each node of the plant with sufficient building blocks (i.e. CO2 and nutes) with sufficient energy (i.e. direct light) to build flowers directly, WITHOUT-SHADE-LEAVES-ACTING-AS-A-BUFFER.”
I think so.
“Speculative Answer Two: "Overdrive"
Some how, the defoliation technique is (hormonally?) stressing the plant to drive it harder, such that there is more transpiration/surface area of the remaining leaf mass. Accordingly, the old nute concentrations are concentrating too much in the new growth, resulting in burns.”
I strongly believe that there is a lot more going on with defoliation than just light. I feel we are seeing a hormonal reaction as well.
d9
__________________
“So, you've had nute burning on plants at a level that previously didn't result in burns.”
yep, the symptoms appeared after DF'ing at the end of stretch.
“You're highest yield to date was a defoliated plant (plucked at the end of stretch). I presume if quality had suffered, you would have discontinued the practice.”
all four of these last plants were DF'd. They produced good quality, potent bud. They really didn't look all that bad, i'm just used to growing plants that have no visible problems.
“Question One:
At one point, the nute concentration was not causing burns, but then it was. Why?”
Good question. I think nitrogen is the culprit. When defoliated at end of stretch I believe nitrogen intake goes way down. The plant is not building much more mass at this point. Root and shoot growth are mostly over.
The fan leaves are like radiators and storehouses. They radiate excess moisture away from the plant via the stomata mechanism and release stored energy for flowering.
I don't think the buds themselves need as much N after stretch. But with fan leaves intact I believe the leaves act as a nutrient buffer for N. With them removed the buffer/control mechanism is gone and the bud formations are forced to handle it alone. In other words I don't think all parts of a plant consume nutrients at the same rate and the bud formations are getting too much N after DF.
this is also supported by my observation that the ph in flower has been running a few points higher in the reservoirs of the DF'd plants than the non-DF'd ones. Remember the discussion above about NO3 driving ph up. With DF we are getting a different consumption rate.
“Speculative Answer One: "Efficiency"
Maybe the older leaves are acting as a store house for mobile nutes. What was being stock piled within the old leaves now has no place to 'overflow' and this increased concentration is resulting in leaf burn.”
I think so.
“Implications: You've reduced your nute concentration to one half, and reduced your take-up by one half, yet your yield has improved/remained stable. Simple math says that your feeding at ~1/4 the strength you used to, which implies a quadrupled efficiency in nute usage of the plant to maintain yield. Where does this come from?”
I mentioned this in the defoliation thread. Cannabis, especially indicas because of where they occur, usually goes through the vegetative stage in the “wet” season and the flowering stage in the “dry” season.
Nutrients are not taken up as readily in drier root conditions. So the nutrient flow for naturally occurring plants is reduced. I think the plant has evolved to store nutrients in advance for this. The fans leaves are the storage bank. With DF we remove the storehouses yet still supply the plant with all the nutrients it can use at any given time.
“While the stability of the solution may result from the wick isolation, the root ball analysis you've done suggests that there is a nearly complete food uptake. So we think the ratios are good. If the ratios are good, and they are being provided in a manner that is constantly available to the plant, why would she need to stockpile mobile nutes? That is, she eats exactly what she needs, and grows flowers. (So, in a perfect situation, older leaves aren't necessary).”
The plant is programmed to stockpile nutrients for flower. The 3-1-4 ratio is great for veg and pre-flower and is good for flower with fan leaves intact.
So with continuous liquid feed fan leaves are not necessary after stretch.
But I do think a correction is called for.
Using the jack's/calcium nitrate combo we have close to a 3-1-4 ratio.
By dropping the dose to ec 1.2 I was able to stop the display.
What I propose to do now is to drop the calcium nitrate altogether in flower and substitute the calcium chloride. As the jack's has 50 ppm NO3 in the base product this would change the ratio to approx a 1-1-4 while letting me bring the overall dose back up to ec 2.1.
if I get burn again i'll back that down until it stops.
“ASIDE
Who is running Jack's Hydro in a fast moving rDWC... cause this might be a solution to somethe problems that caused me to move away from the system).So through the defoliation technique, in conjunction with Jacks, your hitting each node of the plant with sufficient building blocks (i.e. CO2 and nutes) with sufficient energy (i.e. direct light) to build flowers directly, WITHOUT-SHADE-LEAVES-ACTING-AS-A-BUFFER.”
I think so.
“Speculative Answer Two: "Overdrive"
Some how, the defoliation technique is (hormonally?) stressing the plant to drive it harder, such that there is more transpiration/surface area of the remaining leaf mass. Accordingly, the old nute concentrations are concentrating too much in the new growth, resulting in burns.”
I strongly believe that there is a lot more going on with defoliation than just light. I feel we are seeing a hormonal reaction as well.
d9
__________________
Thanks for the taking the time to reply with the thoroughness.
If I had been more precise with my language, I would have described the fan leaves as a 'buffer' rather than a store house, with the implication that the mobile nutrients stored within there are moving in and out as the dynamics of growth dictate.
There seems to be a feeling on many of the boards that the idea that N is more necessary in flower than many of the off the shelf nute's are offering in their flower ratio. I don't have any readily available source material... but chasing the fatman around, he certainly wasn't suggesting dropping anything as low as 1-1-4 through flower (particularly if you've removed so much N buffer).
Fatman was pretty direct (somewhere) about the idea of long plant starvation and aggressive flushes as being unnecessary and actually disadvantageous to plant development. I think his position was a low pH wash for two days before chop, but again, I don't have a link or quote handy.
Carl's links over to Docbud's grows showed that there was no yellowing off of shade leaves throughout the grow supplied by CRFs, and that his maturation period was longer than expected. These ideas make me wonder if the starvation flush practice is artificially maturing plants before they would finish of their own accord.
(If we are relying on broken feeding schedules (i.e. not PPK/DWC/nft/Blumat) that create a cycle of wet/dry based on medium choice, or whatever, and the plants are feeding heavier than our water schedule, we find ourselves increasing nute concentrations to make up for fewer watering cycles. Then, due to evap, we find ourselves locking in salts in medium, and possibly with jacked levels of N in the leaf matter. So we go to extremes to remove these things in a flush, and sufficiently deplete the plants resources that it digests the N (and everything else) buffered in the leaves, but in the process starve it 'to death' and accelerate it's appearance of maturation. With an aggressive two week flush, does everything look 'done'?)
Regardless, you've got enough results lined up to see if it is beneficial with some degree of statistical relevance.
So it looks like you're going to run three control reservoirs now, huh? Are you going to be ready to commit five of the girls to this regime, or just run one through and see how it goes? (I think I'd play it safe and run on girl off the new post stretch ratio, considering the success you've established with the current system in place.)
See what happens when your bored: Next think you know, you'll be incorporating injected O2 into the root zone, and then creating air gaps for misters, and you'll have a full blown HP aero system running. (Just kidding, keep up the dialage.)
Speaking of changing things for the sake of change: Did you ever get around to changing the air pruning pattern in any of your buckets to the alternating slits a la *mistress* and all?
---
Carl, what happened with the sap analysis thread you mentioned a while back?
If I had been more precise with my language, I would have described the fan leaves as a 'buffer' rather than a store house, with the implication that the mobile nutrients stored within there are moving in and out as the dynamics of growth dictate.
There seems to be a feeling on many of the boards that the idea that N is more necessary in flower than many of the off the shelf nute's are offering in their flower ratio. I don't have any readily available source material... but chasing the fatman around, he certainly wasn't suggesting dropping anything as low as 1-1-4 through flower (particularly if you've removed so much N buffer).
Fatman was pretty direct (somewhere) about the idea of long plant starvation and aggressive flushes as being unnecessary and actually disadvantageous to plant development. I think his position was a low pH wash for two days before chop, but again, I don't have a link or quote handy.
Carl's links over to Docbud's grows showed that there was no yellowing off of shade leaves throughout the grow supplied by CRFs, and that his maturation period was longer than expected. These ideas make me wonder if the starvation flush practice is artificially maturing plants before they would finish of their own accord.
(If we are relying on broken feeding schedules (i.e. not PPK/DWC/nft/Blumat) that create a cycle of wet/dry based on medium choice, or whatever, and the plants are feeding heavier than our water schedule, we find ourselves increasing nute concentrations to make up for fewer watering cycles. Then, due to evap, we find ourselves locking in salts in medium, and possibly with jacked levels of N in the leaf matter. So we go to extremes to remove these things in a flush, and sufficiently deplete the plants resources that it digests the N (and everything else) buffered in the leaves, but in the process starve it 'to death' and accelerate it's appearance of maturation. With an aggressive two week flush, does everything look 'done'?)
Regardless, you've got enough results lined up to see if it is beneficial with some degree of statistical relevance.
So it looks like you're going to run three control reservoirs now, huh? Are you going to be ready to commit five of the girls to this regime, or just run one through and see how it goes? (I think I'd play it safe and run on girl off the new post stretch ratio, considering the success you've established with the current system in place.)
See what happens when your bored: Next think you know, you'll be incorporating injected O2 into the root zone, and then creating air gaps for misters, and you'll have a full blown HP aero system running. (Just kidding, keep up the dialage.)
Speaking of changing things for the sake of change: Did you ever get around to changing the air pruning pattern in any of your buckets to the alternating slits a la *mistress* and all?
---
Carl, what happened with the sap analysis thread you mentioned a while back?
Oh, and changing to cal-chloride doesn't prohibit the addition of cal-nit, does it? You could, if it seemed appropriate, run something looking 2-1-4 if you wanted too?
pruning/training/thinning...teehee
1001
fan defoliation similar to thinning. there may be some ratio/% required for plant to process x-amount of y-nutrient solution. over/under that ratio & process malfunction show on/in fans.
feeding >ppm/ec seem to be key...
especially w/ water solubles. they only require minimal fertilization. just certain ratios, certain spikes of some chems/aminos/simple sugars @ key points of develop/maturation....maybe...
they require lots more water (clean) & ph stability (5.0-5.8) than lots of ferts. 1.0 ec ok. maybe spike to 3.0 @ wk 6 or so...
ca-n fed 1 tyme per moon (early)
pk-micros fed 1 tyme per moon (later)
@~ 32oz +/- per feed.
1-5% runoff. end.
so many methods... but >inputs seem <result.
1001
fan defoliation similar to thinning. there may be some ratio/% required for plant to process x-amount of y-nutrient solution. over/under that ratio & process malfunction show on/in fans.
feeding >ppm/ec seem to be key...
especially w/ water solubles. they only require minimal fertilization. just certain ratios, certain spikes of some chems/aminos/simple sugars @ key points of develop/maturation....maybe...
they require lots more water (clean) & ph stability (5.0-5.8) than lots of ferts. 1.0 ec ok. maybe spike to 3.0 @ wk 6 or so...
ca-n fed 1 tyme per moon (early)
pk-micros fed 1 tyme per moon (later)
@~ 32oz +/- per feed.
1-5% runoff. end.
so many methods... but >inputs seem <result.
Last edited:
knna
Member
D9, i would consider the burns after DF to being caused by difficulty of plants to absorb enough water.
That pattern often happen when EC around the root zone is high. That reduces the gap between osmotic pressure, thus roots need more hydraulic power to absorb water. On a plant without DF, with limited ability to increase hydraulic suction, the problem often appear when solution EC is high, raises over a critical thresold.
On the other hand, hydraulic pressure is obtained by transpiration. On a DF plant, this pressure must be way lower than before being DFd. And that means that the critical treshold lowers: a DFd plant will show burn signs at lower EC than without being DF.
That not negate at all the analysis you did about the lower requeriments of N. Its just complementary.
As always we talk about plant's transpiration and nutrients uptake, all we can do is to do educated hypothesis that explain what we see on plants, that may serve us to know how they will do on changing conditions. But this topic is so complex with so many parameters to take in to account that is almost impossible to have a full image of the problem: for example, hydrulic pressure is strongly dependent of Vapor Pressure Defficit, itself dependent of temperature, CO2 level, relative humidity...; I let it out the analysis on purpose, I just wanted to point out that edge and tip burns often are related to whole EC level and transpiration, not to individual elements uptake.
But all people that tried DF have stated that plants transpiration is strongly reduced, especially at first.
We could debate if the new growth of leaves would require adicional amount of N, I can think on theoretic arguments for both yes and no, but the fact D9 experienced is same EC produced burns sign after DF. So I think we must conclude that at least just after DF, it is necessary to lower EC. And later, find an explanation, so curious humans wants to know, but plants will grow great without knowing that explanation
As leaves has a much larger N content than other tissues, if we allow the growth of new leaves N supply cant be cut excessively, IMHO. Same for Calcium, that is requiered for cell's walls building and which uptake is directly proportional to water uptake, opposite to N and other macronutrients that are actively uptaked. So with the strong reduction on water uptake, if Ca proportion in solution keeps the same, whole Ca uptake is going to be near half.
Thus I dont think reducing the calcium nitrate supply is wise. If any, the nitrate chloride. For sure, the only way of knowing it is trying. But I would bet for a reduction on EC level after DF lineal, by just adding plain water to the res. And as leaves grows again, allows EC to go increasing.
That pattern often happen when EC around the root zone is high. That reduces the gap between osmotic pressure, thus roots need more hydraulic power to absorb water. On a plant without DF, with limited ability to increase hydraulic suction, the problem often appear when solution EC is high, raises over a critical thresold.
On the other hand, hydraulic pressure is obtained by transpiration. On a DF plant, this pressure must be way lower than before being DFd. And that means that the critical treshold lowers: a DFd plant will show burn signs at lower EC than without being DF.
That not negate at all the analysis you did about the lower requeriments of N. Its just complementary.
As always we talk about plant's transpiration and nutrients uptake, all we can do is to do educated hypothesis that explain what we see on plants, that may serve us to know how they will do on changing conditions. But this topic is so complex with so many parameters to take in to account that is almost impossible to have a full image of the problem: for example, hydrulic pressure is strongly dependent of Vapor Pressure Defficit, itself dependent of temperature, CO2 level, relative humidity...; I let it out the analysis on purpose, I just wanted to point out that edge and tip burns often are related to whole EC level and transpiration, not to individual elements uptake.
But all people that tried DF have stated that plants transpiration is strongly reduced, especially at first.
We could debate if the new growth of leaves would require adicional amount of N, I can think on theoretic arguments for both yes and no, but the fact D9 experienced is same EC produced burns sign after DF. So I think we must conclude that at least just after DF, it is necessary to lower EC. And later, find an explanation, so curious humans wants to know, but plants will grow great without knowing that explanation
As leaves has a much larger N content than other tissues, if we allow the growth of new leaves N supply cant be cut excessively, IMHO. Same for Calcium, that is requiered for cell's walls building and which uptake is directly proportional to water uptake, opposite to N and other macronutrients that are actively uptaked. So with the strong reduction on water uptake, if Ca proportion in solution keeps the same, whole Ca uptake is going to be near half.
Thus I dont think reducing the calcium nitrate supply is wise. If any, the nitrate chloride. For sure, the only way of knowing it is trying. But I would bet for a reduction on EC level after DF lineal, by just adding plain water to the res. And as leaves grows again, allows EC to go increasing.
knna,
Checking for understanding here:
In our application, 'osmotic pressure' describes the tendency of water to pass through a semi-permeable membrane to ballance concentrations of nutrients on either side of the membrane.
'Hydrolic pressure' is the tendency of water to be drawn upward through the plant to--essentially--fill the void created through transpiration.
In our application, these are opposing forces.
Following defoliation, we've reduced transpiration and therefor reduced the tendency of water to be drawn in/upward through the plants (hydrolic pressure). If the EC is high, we are seeing a tendency to hold more water on that out-side of the semi-permeable membrane, resulting in the difficulty for plants to "absorb enough water." So in defoliation, at a certain threshold, in addition to mechanically reducing transpiration, we've chemically added to that at the root level.
Am I to think that the appearance of leaf burns is the result of the nutes already in the leaves becoming 'concentrated' do to lack of water passing through the system? (That's the jump I'm not really sure about... but makes far more sense than the idea that the plants are taking up too many nutes resulting in burns...)
As an aside, this is consistent with the tendency in growers to increase PPM as plant size increases, because mechanically, the hydrolic pressure can overcome the possessed osmotic pressures related to increasing PPM.
As another aside, this give me insight into the relationship between plants and microbes--the microbe population's bio-cycle modifies the immediate environment around the semi-permeable membrane (i.e. the roots) and thereby modifies the relationship between osmotic and hydrolic pressures.
Thanks for the thought provoking post.
Checking for understanding here:
In our application, 'osmotic pressure' describes the tendency of water to pass through a semi-permeable membrane to ballance concentrations of nutrients on either side of the membrane.
'Hydrolic pressure' is the tendency of water to be drawn upward through the plant to--essentially--fill the void created through transpiration.
In our application, these are opposing forces.
Following defoliation, we've reduced transpiration and therefor reduced the tendency of water to be drawn in/upward through the plants (hydrolic pressure). If the EC is high, we are seeing a tendency to hold more water on that out-side of the semi-permeable membrane, resulting in the difficulty for plants to "absorb enough water." So in defoliation, at a certain threshold, in addition to mechanically reducing transpiration, we've chemically added to that at the root level.
Am I to think that the appearance of leaf burns is the result of the nutes already in the leaves becoming 'concentrated' do to lack of water passing through the system? (That's the jump I'm not really sure about... but makes far more sense than the idea that the plants are taking up too many nutes resulting in burns...)
As an aside, this is consistent with the tendency in growers to increase PPM as plant size increases, because mechanically, the hydrolic pressure can overcome the possessed osmotic pressures related to increasing PPM.
As another aside, this give me insight into the relationship between plants and microbes--the microbe population's bio-cycle modifies the immediate environment around the semi-permeable membrane (i.e. the roots) and thereby modifies the relationship between osmotic and hydrolic pressures.
Thanks for the thought provoking post.
vpd, transpiration, water, etc...teehee
vpd, transpiration, water, etc...teehee
rh...vpd...etc...
relative humidity is an expression of the actual water vapor pressure, expressed as a percentage of the maximum water vapor pressure possible under certain air+atmospheric pressure conditions.
@ room temp (~60*f), 100% humidity exerts a vapor pressure of24 torr (~4.65 pound-force per sq. in.) 1 torr = 1 mmhg/19.3*10^-3 psi...
24*{19.337*10^-3}]=4.65 psi pound-force.
less than (>) 24 torr of vapor pressure exerted on leaves, and leaves sense a vapor pressure deficit.
leaves stomata opening/closing influenced by difference between internal/external vapor pressure. opening/closing of stomata regulates gas exchange+transpiration, which in turn regulates growth/fruiting.
vapor pressure deficit is a lack of water pressure upon plant. this would be a low rh. it is indirect measure of water loss from plant. as plant attemps to balance internal/external vapor pressures, they draw up more water from roots and transpire it into the atmosphere. hence the de-humidifiers used in gardens.
air movement over plant+high temps+low rh reduce plants available water for sugar production. the roots uptake much more water during low rh. but all inter-related to ambient temp(avg. surrounding air temp), actual leaf temp, and root temp.
in general...
lower rh(high vpd)=increased transpiration, translocation, water uptake, greater calcium absorption/transport.
higher rh(low vpd)=slower transpiration, translocation, water uptake, slower evaporation, increased growth.
t,w. & b, h.:
vpd, transpiration, water, etc...teehee
plants seem able to uptake water separately/independent than uptaking nutrients. they also seem able to translocate some elements duering high or low transpiration levels... or, whatever the rh (vpd) is... though, there are some targets...knna said:
counter flow - xylem water flow in the absence of transpiration resulting from water circulation between the xylem and phloem...or, replacing, within the xylem, the water exported from source leaves by way of the phloem...
rh...vpd...etc...
relative humidity is an expression of the actual water vapor pressure, expressed as a percentage of the maximum water vapor pressure possible under certain air+atmospheric pressure conditions.
@ room temp (~60*f), 100% humidity exerts a vapor pressure of24 torr (~4.65 pound-force per sq. in.) 1 torr = 1 mmhg/19.3*10^-3 psi...
24*{19.337*10^-3}]=4.65 psi pound-force.
less than (>) 24 torr of vapor pressure exerted on leaves, and leaves sense a vapor pressure deficit.
leaves stomata opening/closing influenced by difference between internal/external vapor pressure. opening/closing of stomata regulates gas exchange+transpiration, which in turn regulates growth/fruiting.
vapor pressure deficit is a lack of water pressure upon plant. this would be a low rh. it is indirect measure of water loss from plant. as plant attemps to balance internal/external vapor pressures, they draw up more water from roots and transpire it into the atmosphere. hence the de-humidifiers used in gardens.
air movement over plant+high temps+low rh reduce plants available water for sugar production. the roots uptake much more water during low rh. but all inter-related to ambient temp(avg. surrounding air temp), actual leaf temp, and root temp.
in general...
lower rh(high vpd)=increased transpiration, translocation, water uptake, greater calcium absorption/transport.
higher rh(low vpd)=slower transpiration, translocation, water uptake, slower evaporation, increased growth.
t,w. & b, h.:
some pl@nts just grow lots of leaves... most gardenrs seek fruit. remove leaves to encorage fruit... maybe, select best pruning/training/thinning method for specific cultivar...
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Quotes by ImaginaryFriend
“Thanks for the taking the time to reply with the thoroughness.
If I had been more precise with my language, I would have described the fan leaves as a 'buffer' rather than a store house, with the implication that the mobile nutrients stored within there are moving in and out as the dynamics of growth dictate.
There seems to be a feeling on many of the boards that the idea that N is more necessary in flower than many of the off the shelf nute's are offering in their flower ratio. I don't have any readily available source material... but chasing the fatman around, he certainly wasn't suggesting dropping anything as low as 1-1-4 through flower (particularly if you've removed so much N buffer).
Fatman was pretty direct (somewhere) about the idea of long plant starvation and aggressive flushes as being unnecessary and actually disadvantageous to plant development. I think his position was a low pH wash for two days before chop, but again, I don't have a link or quote handy.
Carl's links over to Docbud's grows showed that there was no yellowing off of shade leaves throughout the grow supplied by CRFs, and that his maturation period was longer than expected. These ideas make me wonder if the starvation flush practice is artificially maturing plants before they would finish of their own accord.“
Fatman and Docbud were not defoliating. Before DF'ing I had no yellowing. I also had no overferting symptoms. I've grown plants start to finish with flora nova bloom and it's low N with no problem. In retrospect I feel that they were under fed in veg. I'm not proposing that here as i'm running full strength jack's/calcium nitrate in veg so far.
I don't know, something burned the plants. Looking at all the possibilities I think it is either N or K with N being the most likely suspect because of it's extreme mobility. Switching the formula is the only way to find out for sure. Last night I mixed a batch of 2.1 ec using jack's and calcium chloride. This just cuts N to about the levels of flora nova bloom. If I get burn i'll know it's overall concentration instead of just N.
“(If we are relying on broken feeding schedules (i.e. not PPK/DWC/nft/Blumat) that create a cycle of wet/dry based on medium choice, or whatever, and the plants are feeding heavier than our water schedule, we find ourselves increasing nute concentrations to make up for fewer watering cycles. Then, due to evap, we find ourselves locking in salts in medium, and possibly with jacked levels of N in the leaf matter. So we go to extremes to remove these things in a flush, and sufficiently deplete the plants resources that it digests the N (and everything else) buffered in the leaves, but in the process starve it 'to death' and accelerate it's appearance of maturation. With an aggressive two week flush, does everything look 'done'?)”
I think the whole wet/dry feeding and watering thing started with people growing in containers of soil as a response to soil's loss of air porosity when wet. This loss of air porosity absolutely required an extended dry period to get enough o2 to the roots to keep the plant alive. With a container h2o retention is much greater than the open soil column where everything moves right through. As we have discovered this wet/dry cycle builds up nutrients in the container. This build up needs some flushing to get rid of excess.
However, with modern potting media which have better breathing characteristics than soil this tendency is greatly reduced and with it the need for extensive flushing.
With the ppk the tendency to accumulate salts is all but eliminated.
The plant will have an overall better growth rate when continuously presented with the proper ratios of air, water, and nutrients.
“Regardless, you've got enough results lined up to see if it is beneficial with some degree of statistical relevance.”
maybe
“So it looks like you're going to run three control reservoirs now, huh? Are you going to be ready to commit five of the girls to this regime, or just run one through and see how it goes? (I think I'd play it safe and run on girl off the new post stretch ratio, considering the success you've established with the current system in place.)”
i'm running 2 separate volume tanks. One for veg and one for flower. I think there will be enough N in the plant tissue and medium left over from veg to carry the plant through the stretch period.
“See what happens when your bored: Next think you know, you'll be incorporating injected O2 into the root zone, and then creating air gaps for misters, and you'll have a full blown HP aero system running. (Just kidding, keep up the dialage.)”
Don't think I haven't thought about it.
“Speaking of changing things for the sake of change: Did you ever get around to changing the air pruning pattern in any of your buckets to the alternating slits a la *mistress* and all?”
No, i'm reading and measuring stuff still. I'm trying to get an idea about how much “hole” is needed for a given amount of sidewall. I think 3-5% is the way it's lookin
---
“Carl, what happened with the sap analysis thread you mentioned a while back?”
yeah carl, what happened, dude?
“Thanks for the taking the time to reply with the thoroughness.
If I had been more precise with my language, I would have described the fan leaves as a 'buffer' rather than a store house, with the implication that the mobile nutrients stored within there are moving in and out as the dynamics of growth dictate.
There seems to be a feeling on many of the boards that the idea that N is more necessary in flower than many of the off the shelf nute's are offering in their flower ratio. I don't have any readily available source material... but chasing the fatman around, he certainly wasn't suggesting dropping anything as low as 1-1-4 through flower (particularly if you've removed so much N buffer).
Fatman was pretty direct (somewhere) about the idea of long plant starvation and aggressive flushes as being unnecessary and actually disadvantageous to plant development. I think his position was a low pH wash for two days before chop, but again, I don't have a link or quote handy.
Carl's links over to Docbud's grows showed that there was no yellowing off of shade leaves throughout the grow supplied by CRFs, and that his maturation period was longer than expected. These ideas make me wonder if the starvation flush practice is artificially maturing plants before they would finish of their own accord.“
Fatman and Docbud were not defoliating. Before DF'ing I had no yellowing. I also had no overferting symptoms. I've grown plants start to finish with flora nova bloom and it's low N with no problem. In retrospect I feel that they were under fed in veg. I'm not proposing that here as i'm running full strength jack's/calcium nitrate in veg so far.
I don't know, something burned the plants. Looking at all the possibilities I think it is either N or K with N being the most likely suspect because of it's extreme mobility. Switching the formula is the only way to find out for sure. Last night I mixed a batch of 2.1 ec using jack's and calcium chloride. This just cuts N to about the levels of flora nova bloom. If I get burn i'll know it's overall concentration instead of just N.
“(If we are relying on broken feeding schedules (i.e. not PPK/DWC/nft/Blumat) that create a cycle of wet/dry based on medium choice, or whatever, and the plants are feeding heavier than our water schedule, we find ourselves increasing nute concentrations to make up for fewer watering cycles. Then, due to evap, we find ourselves locking in salts in medium, and possibly with jacked levels of N in the leaf matter. So we go to extremes to remove these things in a flush, and sufficiently deplete the plants resources that it digests the N (and everything else) buffered in the leaves, but in the process starve it 'to death' and accelerate it's appearance of maturation. With an aggressive two week flush, does everything look 'done'?)”
I think the whole wet/dry feeding and watering thing started with people growing in containers of soil as a response to soil's loss of air porosity when wet. This loss of air porosity absolutely required an extended dry period to get enough o2 to the roots to keep the plant alive. With a container h2o retention is much greater than the open soil column where everything moves right through. As we have discovered this wet/dry cycle builds up nutrients in the container. This build up needs some flushing to get rid of excess.
However, with modern potting media which have better breathing characteristics than soil this tendency is greatly reduced and with it the need for extensive flushing.
With the ppk the tendency to accumulate salts is all but eliminated.
The plant will have an overall better growth rate when continuously presented with the proper ratios of air, water, and nutrients.
“Regardless, you've got enough results lined up to see if it is beneficial with some degree of statistical relevance.”
maybe
“So it looks like you're going to run three control reservoirs now, huh? Are you going to be ready to commit five of the girls to this regime, or just run one through and see how it goes? (I think I'd play it safe and run on girl off the new post stretch ratio, considering the success you've established with the current system in place.)”
i'm running 2 separate volume tanks. One for veg and one for flower. I think there will be enough N in the plant tissue and medium left over from veg to carry the plant through the stretch period.
“See what happens when your bored: Next think you know, you'll be incorporating injected O2 into the root zone, and then creating air gaps for misters, and you'll have a full blown HP aero system running. (Just kidding, keep up the dialage.)”
Don't think I haven't thought about it.
“Speaking of changing things for the sake of change: Did you ever get around to changing the air pruning pattern in any of your buckets to the alternating slits a la *mistress* and all?”
No, i'm reading and measuring stuff still. I'm trying to get an idea about how much “hole” is needed for a given amount of sidewall. I think 3-5% is the way it's lookin
---
“Carl, what happened with the sap analysis thread you mentioned a while back?”
yeah carl, what happened, dude?
D9,
So the intent is to run a veg volume res w/ Jacks + cal-nit, and run all of the flower with Jacks + cal-chloride? You'll not defoliate in flower until stretch is done, so that any N stockpiles in the leaves doomed to be plucked can get used up in stretch... at which point, you speculate it isn't necessary anyway. (Right?)
With regard to the Docbud and Fatman references:
-Fatman's various nute schedules never drop off N severely when transitioning to veg to flower. Your thought is with the defoliation process, you're removing the buffering inherent in the larger shade leaves, and therefor must dump some N to compensate(?).
-When Doc was running CRFs, his pics showed old leaves, but not the yellowing often associated with a 'clean flush'. Additionally, the plants seemed to take longer to mature than he expected. My observation was that it may be the process of flushing (starving) a plant that makes it appear to finish on a certain date--that is, the N depletion (and every other nute) might be prematurely finishing the plant. I guess that was a general observation, and not directed at your grow precisely.
On the bucket air holes: My thinking was about the minimum width of the slit to effectively stop circling roots, rather than the ratio of solid to perf. Is an 1/8inch sufficient... or can you get away with 3/32... blah blah... every inch... call each slit three inches long, staggered. I dunno.
Look forward to the consequences of your adaptations...
So the intent is to run a veg volume res w/ Jacks + cal-nit, and run all of the flower with Jacks + cal-chloride? You'll not defoliate in flower until stretch is done, so that any N stockpiles in the leaves doomed to be plucked can get used up in stretch... at which point, you speculate it isn't necessary anyway. (Right?)
With regard to the Docbud and Fatman references:
-Fatman's various nute schedules never drop off N severely when transitioning to veg to flower. Your thought is with the defoliation process, you're removing the buffering inherent in the larger shade leaves, and therefor must dump some N to compensate(?).
-When Doc was running CRFs, his pics showed old leaves, but not the yellowing often associated with a 'clean flush'. Additionally, the plants seemed to take longer to mature than he expected. My observation was that it may be the process of flushing (starving) a plant that makes it appear to finish on a certain date--that is, the N depletion (and every other nute) might be prematurely finishing the plant. I guess that was a general observation, and not directed at your grow precisely.
On the bucket air holes: My thinking was about the minimum width of the slit to effectively stop circling roots, rather than the ratio of solid to perf. Is an 1/8inch sufficient... or can you get away with 3/32... blah blah... every inch... call each slit three inches long, staggered. I dunno.
Look forward to the consequences of your adaptations...
