passive plant killer

[ImaginaryFriend]

*mistress*,

Checking for understanding:

Vapor Pressure Deficit describes the difference between internal hydraulic pressures and external hydraulic pressures.

It's been observed that plants tend to grow the best with a VPD of 3-7g/m^3.

Presumably, this optimizes the presence of all the necessary components of growth in the correct regions (CO2, nutes, the correct light energy to excite everything into a new chemical constituents).

Plants fed water directly transpire lots (low external osmotic pressure offers little resistance to the hydraulic pressure derivative from transpiration).

Nutrients will move throughout the plant independent of transpiration.

I'm missing a little something here, in that I don't see a connection here to plants being able to take up water independently of nutrients from your post. I see rapid transpiration in the absence of opposing osmotic forces. I see osmosis and chemical solutions seeking equilibrium in the absence of transpiration. I don't see a plant pulling just water out of a solution (i.e. selectively feeding). But maybe that wasn't your implication.

Anyway, I've been avoiding the whole VPD discussion for a while. Your post in this context was very helpful in starting to get my brain around it.

VPD (hydraulic pressure), CO2, nute concentrations (osmotic pressure), light levels and DNA are clearly a balancing act. I see why knna just skipped the whole analysis.

That said, understanding why he skipped the analysis is better than not even knowing that there was one to be done.

This particular page on this particular thread has been particularly thought provoking.

Thanks everyone.

 

[SCROG McDuck]

I have no idea what y'all are talking about but (<technically!
I know it is important for my future endevors and understanding..

I will re-read untill I can manage your implications intelligently...
It ain't easy being me.

Thanks..

 

[Carl Carlson]

what we need is for one of these California boys to man up and take some "medical" plant samples to the local extension office for up to date tissue testing.

https://www.icmag.com/ic/showthread.php?t=181405

offsite

 

[Fat J]

Bring me samples ^^ ill test em.

This is very interesting, ive never seen such a good explanation of these processes - i dropped bot beofre they got to the good stuff... I'm not stoned enough to totally smash my brain around it all, but I'll get some stronger weed and come back n re-read... Makes a lot of sense tho, I prefer systemic understanding to incidental knowledge. Hehe, this was sposta be my non-technical hobby.

So if the nute solution is 2 strong, u get burns due to osmotic pressure drawing moisture out of the plants & reduced water increases ec in plant to intolerable levels? Whats better, high air pressure or low air pressure? Need stronger weed... ill be back.

 

[Carl Carlson]

Fat J, I don't live anywhere near California.

Are you saying you have personal access to equipment? I think all we need are a few tests.

Indica dom., Sativa dom. and 50/50 - all three during late veg and late bloom...

 

[Fat J]

Ya, got a glass-on-glass carbonizer/extractor (with ice catcher) - also got lotsa zigzag cylander test strips - orange package... not to mention the handheld tempered silicon/carbon based smoketragraphical analyzer.

late bloom only plz, I dont "analyze" veggin pot, nor premature. must be done, ripe, cured...all sample should be at least a quarter pound.

Thanks in advance - please note Fat J labs is a qualitative-only testing facility, no quantitative results will be provided.

 

[ImaginaryFriend]

@Fat J


You asked: "Whats better, high air pressure or low air pressure?"


knna summed it up pretty nicely: "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"...

An example: My temps are high. My humidity is low. So I am set up for a lot of transpiration. Today, I took my fan off oscillating mode. I think the girls liked it. Why? I'm hoping to increase humidity surrounding the leaves to slow transpiration... because I'd need like 90% humidity with the temps I'm running to achieve the VPD of 3-7g/m^3.

But as I am directly venting, I'll never be able to get the RH up to the 70% this time of the year.

So, I'm playing with increasing my EC a bit. I think they liked it higher than I'm running it now, with no signs of chem burns. (Now I wonder if it was slowing the rate of transpiration by countering the hydraulic pressure with osmotic 'resistance'. I dunno.) But I'm feeding back into the 2.2-2.4 range from my top-off res (volume res in D9's terminology) and everything seems pretty cool.

 

[Carl Carlson]

Fat J - very funny

 

[ImaginaryFriend]

Here's the girl who lives on the right just after transplant:


Here she is today (16 days veg), with my fumbling changes:


I think her roots are finally starting to get somewhere.

 

[delta9nxs]

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.

hey, knna! sorry for not answering sooner but i just spent all day trimming another one.

i think the scenario you have described is the most likely, that the differences in transpiration caused the ec to be, at least temporarily, too high.

what i'm trying is just a quick experiment. if they get any burn again i'll know it's just overall ec and i will revert back to the calcium nitrate in flower. only at a lower dose.

as you said, the whole subject of transpiration and vpd is very complex with a large number of variables.

certainly my correction to ec 1.2 stopped the display.

defoliating brings a new set of variables into play.

with this particular experiment i want to see if the fans leaves are acting as a nitrogen buffer and controller. maybe like a tidal pool catches a large surge of water and then releases it in a controlled fashion.

what i have done is remove 66% of the nitrate while keeping the same ec as before DF.

if i do not get burn it means such a mechanism exist.

by removing a portion of the N such a mechanism could be exposed.

this could also very easily be coincidental to the combined effect of timing and defoliating.

at the end of stretch, when maximum plant stature has been achieved, N is no longer needed in the same quantities.

i have been radically defoliating at precisely that time.

perhaps changing the timing of when you defoliate could stop the burn. or by doing it progressively instead of all at once. or dropping ec.

i don't know, i'm just playing around. but i will know about this by the end of next week.

you did a really nice paper on vpd, temp, and rh on gc several years ago, maybe you could link us to it.

later on, d9

 

[*mistress*]

Vapor Pressure Deficit describes the difference between internal hydraulic pressures and external hydraulic pressures.
...
Nutrients will move throughout the plant independent of transpiration.

I'm missing a little something here, in that I don't see a connection here to plants being able to take up water independently of nutrients from your post. I see rapid transpiration in the absence of opposing osmotic forces. I see osmosis and chemical solutions seeking equilibrium in the absence of transpiration. I don't see a plant pulling just water out of a solution (i.e. selectively feeding). But maybe that wasn't your implication.
...
VPD (hydraulic pressure), CO2, nute concentrations (osmotic pressure), light levels and DNA are clearly a balancing act. I see why knna just skipped the whole analysis.

the topic can become very technical...
why an experimental/basic botany-plant growth sub-forum has been proposed. no interest...

vapor pressure deficit is the plant sensing the difference between internal & external water pressures. the plant desires 100% humidity, like rain forest. the internal water pressure inseide leaf is 100%... so, any >than that & plant senses 'deficit'. the amount of deficit is, yes, dependent on light levels, etc... there are charts that have specific temp & rh for desired vpd. c02 concentration also affects opening stomata, which is where the veins on the leaves lead to & water (as vapor) is released in to atmosphere... why fans help: to carry away water...

while nutrients are capable of being moved by transpiration, that is not the primary function of transpiration. the primary function seems to be the transport of water thru-out the plant.

some elements, like the heavy metal calcium, generally immobile, seem to be able to move more w/ lower rh, which is a higher vpd...

vapor pressure deficit is...
leaves have almost 100% vapor pressure inside of the leaves. they sense outside of leaves. vapor pressure deficit is lack of water pressure on outisde of plant. low rh=high deficit... this difference between in/out pressures signals stomata to open or close. opening/closing stomata regulate temps (plant), gas exchange, etc...

the external pressure is generally measured in rh, or relative humdity. higher humidity is what plants desire, but that may cause disease & pests...

96% of plant is not nutrient
hydrogen - 6% - from h20
carbon - 45% - from air
oxygen 45% - from air

only 3.5% of a plant is nutrients.
n-1.5%
k-1
ca-.5
mg-.2
p-.2
s-.1
ch-.01
b-.002
fe-.01
mn-.005
zn-.002
cu-.0006
mo-.00001

the qoute ^ in previous post points out that transpiration is different than counter-flow, or nutrient assimilation. the graphs are not linear. nor are the graphs of stomata opening/closing.
the stomata actually open & close several tymes during the day...
what seems is that the plant requires water 24/7... it does not requires 1000ppm, or even 500ppm, or even 250 ppm constantly. especially w/ certain mediums like coco, which keep certain cations stored. the leaves make food & store it in roots. the roots can then send certain elemnents upwards...

even the roots are so specialized that certain elemtns are absorbed on differnte parts of the root...

a feed-water-water-feed regime will work w/ most plants. a feed-feed-feed regime mayu work w/ low ppm, as more active elements are in solution, less water is avaialable... they require solution to be 95% water 100% of tyme...

hope this helps.

 

[delta9nxs]

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...

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...

hi, i've got this whole paper saved, but here are a few more excerpts from it.

Transpiration, a prerequisite for long-distance transport of minerals in plants?
1.W. Tanner*,† and
2.H. Beevers‡
+ Author Affiliations
1.*Institute of Cell Biology and Plant Physiology, University of Regensburg, 93040 Regensburg, Germany; and ‡Biology Department, University of California, Santa Cruz, CA 95064
1.Contributed by H. Beevers
*
Next Section
Abstract
The major “benefit” alleged to accrue from transpiration (the evaporative loss of water from plant surfaces) is that it is essential for the long-distance transport of mineral ions, but the possible interrelation between these two processes has rarely been tested. Transpiration was experimentally dissociated from mineral supply by growing sunflowers (Helianthus anuus) in hydroculture and providing mineral nutrients only during the nights. These plants grew as well as a control group that received nutrients only during the day and transpired 12–15 times more water during the exposure period. It thus appears that convective water transport in the xylem, brought about by root pressure and the resultant guttation, “growth water,” and Münch's phloem counterflow is in itself sufficient for long-distance mineral supply and that transpiration is not required for this function.
Although there is no experimental evidence to support the general proposition, it is commonly believed that transpiration, the evaporative loss of water from plant leaves, is required for the long-distance transport of inorganic nutrients in the xylem of higher plants (1, 2). Of course, there is no dispute that the increased flow of water during transpiration elicits a corresponding increase in the rate at which dissolved solutes move upward in the xylem elements. The specific question we address is whether this acceleration, mediated by transpiration, is essential for plant growth. We argue that other forces, which result in solute movement upward in the xylem, are adequate for the delivery of nutrients and that transpiration, per se, is not necessary for this or indeed any vital function in plants. The concept concerning the role of transpiration in plant nutrition goes back to Julius Sachs (3), who explained the enrichment of minerals within plants as compared with their concentration in soil water simply by analogy to distillation. It is now recognized that the metabolic uptake of ions and the passive uptake of water are independent processes. Nevertheless, over the years, the view had developed that some useful function must be fulfilled by the large amount of water moving through plants because of transpiration, and long-distance transport of mineral nutrients has received the most attention. Strong views questioning such a role for transpiration have occasionally been expressed (4, 5), but these have not been supported by experiment. It has been shown by growing plants under high humidity that transpiration could be reduced by >60% without any effect on growth or mineral content (6, 7), but the suggestion that transpiration was unimportant did not go unchallenged (8). The major difficulty in studying the contribution of transpiration to long-distance transport of minerals is that it is not possible strictly to maintain 100% relative humidity (R.H.) around plant leaves in the light. The unavoidable temperature difference between a leaf absorbing light and the water-saturated air of a growth chamber prevents the maintenance of 100% R.H. in the intercellular spaces of the leaf and the immediate neighborhood of its surface. Water loss due to transpiration cannot be reduced by more than about 70% (7). We now describe a different experimental approach to address this issue. Transpiration and mineral uptake were temporally dissociated by growing sunflower plants in a 12 h light/12 h dark regime under which minerals were supplied only in the dark, during which time the growth chamber was maintained at 100% R.H. The water loss during the night exposure to nutrients was reduced by a factor >10 over a control group receiving nutrients only during the light, yet the growth and mineral content of the plants was unaffected.

 

[delta9nxs]

here is another part:

Discussion
The main open question is, how do plants manage their long-distance mineral transport under conditions when the transpiration stream is reduced to very low levels? It is obvious, in the first place, that the same amount of ions can be translocated only with 1/10 of volume flow if the ion concentration in the xylem is increased accordingly. Because the actual mineral uptake is not affected by the decrease in transpiration, as shown previously (9–11), and also as shown for the growth conditions applied here (Tables 1 and 2), this assumption is unavoidable and has indeed been experimentally demonstrated (13). Second, however, there exists transpiration-independent water flow in the xylem. Growth water (14) and “Münch's counterflow” (replacing, within the xylem, the water exported from source leaves by way of the phloem, “Saftzirkulation”; ref. 15), are minor fractions in heavily transpiring plants, but constitute a significant portion of water when transpiration is reduced.
Applying the same criteria as we did previously (7), we can estimate the amount of water moving independently of transpiration. In Table 5 this is done for the MN-plants of Table 1. The increase in fresh weight of the shoot amounted to 450 g; 90% of it was taken as growth water. The estimation of Münch's counterflow is based on the assumption that two-thirds of the dry weight increase (root and 50% of the shoot) plus an additional 20% used up by respiration is photosynthesized in the top part of the plant and transported downward. Assuming further an average sucrose concentration of 10% in the sieve tubes, the volume flow in the phloem amounts roughly to 400 ml. This has to be compensated for by a corresponding water volume flowing upward in the xylem. Finally, the water movement caused by root pressure is taken as 150 ml. This is based on the fact that guttation drops appeared only on MN-plants during the night, and the difference in the water lost during the night between MN- and MD-plants was 150 ml (Table 1). Thus, a volume of close to 1 liter would be transported independently of transpiration equaling approximately the amount of water moving because of residual transpiration in MN-plants during the night (Table 5). Therefore, these 2 liters of water of MN-plants transport the same amount of minerals as the 15 liters of water (13.9 liters by transpiration and ≈1 liter by transpiration-independent water flow) in the MD-plants.
View this table:
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Table 5
The extent of residual transpiration and transpiration-independent water flow in the MN-plants of Table 1
It has to be pointed out that transpiration-independent acropetal water flow in the xylem has recently been elegantly demonstrated with submerged plants by Pedersen and Sand-Jensen (16, 17). These authors also demonstrated that this water transport was not solely because of root-generated pressure, because submerged shoots—the root being cut off—show this phenomenon, too (17). This is most likely caused by negative water potentials arising because of growth (“growth water”). Finally, H2O circulation in the sense of Münch's proposal was proved by NMR using intact Ricinus plantlets (18). Half of the water moving acropetally was shown to recirculate under the experimental conditions applied.
One may even question, therefore, whether the very low amount of transpiratory water loss, by way of transpiration, that took place in our experiment during the night is essential for plants in the context earlier discussed by Smith (8). Clearly, the transpiration-independent volume flow observed and a concomitant increase in ion concentration by a factor of about 2 would completely suffice for optimal supply of mineral nutrients, and such an increase is not unreasonable. Thus Allen et al. (19) found that K+, the main osmotically active ion in the xylem, amounts to about 1 mM in a transpiring plant. In our MN-plants we have to assume, therefore, that the concentration of K+ increased to about 7.5 mM, because 2-liter volume flows in MN-plants bring about the same result as 15 liters in MD-plants. Extrapolating to a complete absence of transpiration—just as a “Gedanken experiment”—a rise in the K+ concentration to about 15 mM would be required. This is less than 20% of the K+ content of typical plant cells. It would not be expected, therefore, that such an increase in concentration would create an osmotic problem, although living cells of the stem would lose some water to establish a new equilibrium.
It could be argued that what may be possible for sunflowers does not hold for trees, because root pressure is by far too low for trees 100 m high. As can be seen in Table 5, even for sunflowers water flow because of root pressure (guttation) is the least important component of transpiration-independent convective water transport. Based on a photosynthesis rate of 15 mg of CO2 fixed per dm2 of leaf area per hour and on the assumption that a mature leaf exports half of the photosynthate as sucrose solution by way of the phloem, one can estimate that within less than 4 days a water potential of less than −2.0 MPa would arise in the absence of any transpiration, a value large enough to pull water up a 100-m-tall tree.
Would the results reported herein have been the same if the experiments had been conducted in soil? Accessibility of ions for roots has been claimed to be positively affected by transpiration (12). However, it has been calculated that mass flow of water to roots as compared with diffusion affects only the availability of phosphate, and even for this anion, the contribution of mass flow has been estimated to be less than 10% (20, 21).
After reducing the rate of transpiration by more than 90% without observing so much as a hint of an adverse effect on growth, and pointing out that forces other than transpiration are fully capable of moving solutes up the xylem, we conclude that transpiration is not essential for long-distance mineral transport. Only a convincing experimental demonstration that the remaining 7% of transpiration is of some special significance would now sustain the contrary view.

 

[delta9nxs]

it looks like i might be barking up the wrong tree with N. K may be responsible for what i see but i have no easy way to check for it as it's in the base formula. if it is K the only solution i have using jack's is to cut ec. we'll know in a few days.

 

[knna]

.

 

[knna]

Hey, Delta, I see you followed my reasoning.

I think that is good to know the processes involved on any think if we want to control it. But in biology, some times is impossible to know all abaut all factors acting at same time and each one influencing the others.

In my last post I just pointing out something that in reality may be very complex to explain, but refered to our growing practices, may be resumed very simple.

Hidrolic pressure (thank for the correction, IF, I tend to use spanish for latin derived words, and they not always are the exact for english) plays a role on the ability of plants to uptake water.

(We can discuss if that role is more or less important, but play its part of the mecanism involved on it).

I associate that pattern of leaves, with browning of edges, with shortage on the uptake of water. Notice that the shortage in water itself dont cause it directly it, but a reaction of the plant due to it (a severe loss of water results on a loss of leave's turgor, but before it, plant reacts to adapt to a lower water uptake, whatever the reason that caused it). We can see that pattern typically on a overfert, but too when roots has been damaged (drown, extreme temperatures or ph, mechanical damage...) and when enviromental parameters become extreme (resumed on VPD too high or too low, but generally its associated to too high). Rarely, its caused by low CO2 (not enough ventilation), as it causes a similar reaction of the plant.

So my point is that when roots, whatever the reason, cant uptake enough water, that pattern appears. So its not correlated to nutrients uptake directly.

When all things being equal, if we DF a plant, hidrolic pressure is reduced and thus, ability to uptake water drops. EC (properly, salt's concentration, EC is just our way to indirectly measure it, especially indirect when a medium is involved, not Water Cultures) around the roots inform us about the point at water uptake becomes difficult. With hidrolic pressure reduced, it is to expect that roots have difficulties at lower EC.

Resuming it in few words: reduced hidrolic pressure result on signs of overfert at lower EC levels, because its part of the water uptake mechanism.

Said that, I would like to add that sometimes this discussion appear because we use the wrong words. One thing is the pure "overfert", meaning we gave too much nutrients to the plant creating a type of problems, and other, that we used an EC too high (for the general parameters of a given plant, unique for each plant and setup) that result on difficulties uptaking water.

When we see those signs, we quickly say that its "overfert", but not necessarily it is. Maybe the plant may use those nutrients fine, the problem is the high EC aroud roots difficulties water uptake. Conceptually, they are different things.

If we give excess of a element, its uptake rarely causes toxicity itself, especially if we talk about macronutrients, that usually plants can store in way larger amounts than they need at the moment. There are some elements which accumulation creates toxicity at low levels (we talk about urea some days ago here, for example), but they are mostly microelements.

The problem created by excess on a element usually not appear as toxicity, but as deff of other element.

Especially, nitrate nitrogen very unlikely will cause toxicity. Excess of it must be really very excessive. Browning of egdes is too associated to K deff, but NO3- almost not interfere with K+ uptake, that is an element with fast active uptake by plants and only way roots cant uptake enough is by it not being present on the media (usually, its a "salt lockout", strong excess of Ca and or Mg cations).

Anyway, delta9nxs, the best way of knowing how plants react is giving two different treatments and observe what works better. I bet that plain lower EC, without altering nutrient profile, will work better after DF. But plants will tell.

Just be aware that Ca is an element which uptake is strongly linked to water uptake, and that if transpiration is reduced and Ca parcentage on the nutrient profile drops too, a deff of Ca may occur. I always try to avoid Ca deff because its the deff that cost more in term of yield: anyone better than it.

 

[*mistress*]

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.

instead taking bunch leaves @ 1 moment, try take only those few that gro into center of canopy.
there maybe actually different types of fan leaves. the fans connected to stem/branches usually grow thicker w/ purplish petioles. they really never required. they just get big & shade the tree.

the secondary fans attach to branches. the ones that gro into middle of plant take every 1-3 days. this makes for no 'shock' when 'defoliate'.... they just get used to making more leaves, faster...

as for ferts... maybe in imagination apply similar water soluble. but... 5-1x-2x go in separate.... ca-nit in 1 container. pk-micro in seprate tank. hrs 1-4 of sun get cal. hrs 8-12 get pk-micros.

mkp may help in mid-bloom. 1/2 tsp (2.5g) mkp =
150-p
186-k

if it is nitrogen, can easily corect w/ foliar spray ca-nit @ ph 6.2-6.5... leaves prefer alkaline...surfacant added...

'flushing' w/ mg & ca from separate tank(s) @ 1/wk also keep healthy. cal deficiency show @ top...mag @ lower leaves as plant translocates to higher leaves. cal very little translocation (heavy metal), but does move more when lower rh...

ec 1.2...ec 2.0...

they go to 3.5 (2500ppm) @ wk 6... or more... fruit sugar/ec spike

maybe, check ph & lower to 5.0-5.5 constant, to keep micro-nutrients held in solution. they maybe really like acid more than alkaline.... it maybe ph that cause lock-out/burn/deficiency...

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.

was ph adjusted when lowered ec?

it looks like i might be barking up the wrong tree with N. K may be responsible for what i see but i have no easy way to check for it as it's in the base formula. if it is K the only solution i have using jack's is to cut ec. we'll know in a few days.

feeding ca-nit & rest of solyution separate, +... hard to over-dose on k...

defoliation may/may not be cause of 'burn' or deficiency... the plant can easily make more leaves when healthy, w/out any fert burn.

but... severe leaf thinning not necessary. just take the leaves groing into center of plant, that actually shades plant. every 1-4 day. that enough... maybe...

 

[delta9nxs]

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...

good morning! i think i'm causing some confusion here.

while i have been df'ing in flower at end of stretch and will continue to do so with the plants i have already grown too large, i have also started to play around with df'ing in veg.

this is because my plants are getting too big to handle and i'm overgrowing the veg area badly.

i've been breaking them a lot lately moving the plants into flower and any time i try to move around in either area.

last night i removed the 8th position in veg that i had started a month or so ago.

i was getting to a point of diminishing returns as far as light application is concerned.

too much plant material to light effectively.

i have the 2 44 gal brutes as volume tanks and separated them a while back so i could run different feed regimes in veg and flower.

what i'm trying with the calcium chloride is just an experiment.

you may be on to something about the flush impeding final bud development.

the hang up i'm running into with vertical slits is finding a way to cut them accurately.

i'm thinking 1/4 inch slits.

 

[delta9nxs]

Here's the girl who lives on the right just after transplant:


Here she is today (16 days veg), with my fumbling changes:


I think her roots are finally starting to get somewhere.

i am amazed that plant looks so good considering the temps. apparently something is negating the effect of all that heat.

 

[delta9nxs]

I have no idea what y'all are talking about but (<technically!
I know it is important for my future endevors and understanding..

I will re-read untill I can manage your implications intelligently...
It ain't easy being me.

Thanks..

Scrog McDuck! is that you, knipple?