Coco watering frequency when transplanting clones

[Orange's Greenhouse]

Very nice paper showing that fertilization on rock wool and coco should be identical (the supposed higher need for calcium and magnesium is clearly disproven here).
Comparison of Coconut Coir, Rockwool, and Peat Cultivations for Tomato Production: Nutrient Balance, Plant Growth and Fruit Quality

Did you read that paper? They show that coir has very high potassium. If you mix that with a feed that has increased calcium and magnesium (or low K if you want to read it like that) the sum is a balanced nutrient solution.
Calcium also has higher affinity for coir than K so you need extra calcium to make up for the Ca taken out of solution.

 

[Dr.Dutch]

Did you read that paper? They show that coir has very high potassium. If you mix that with a feed that has increased calcium and magnesium (or low K if you want to read it like that) the sum is a balanced nutrient solution.
Calcium also has higher affinity for coir than K so you need extra calcium to make up for the Ca taken out of solution.

Not just once. For coco from the Jiffy Group and generally in studies that properly examine coco, it should be washed and buffered coco (although the paper cannot confirm this for sure since the specific substrate is not explicitly mentioned).
However, when we look at the study, we can clearly see that it must be buffered coco. Plants would almost certainly fail on unbuffered without specific fertilization (this is likely because calcium and magnesium are drawn from the nutrient solution until the cation exchange capacity is saturated with the double bonds of calcium and magnesium).

As I said, the study shows the same thing I observe:
I manage Potassium:Calcium:Magnesium ratios exactly as one would for DWC, and on Canna Coco Pro, I never see any calcium or magnesium deficiencies.

You don't need to consider the substrate values in practice, the potassium in it is quickly depleted. That’s no reason to add extra calcium until late flowering.

As said: Normal Ca/Mg values and all is good. Tried to copy the coco fertilizer first, but turned out to be bullshit (Undiluted NS).

 

[LJ farming]

Not just once. For coco from the Jiffy Group and generally in studies that properly examine coco, it should be washed and buffered coco (although the paper cannot confirm this for sure since the specific substrate is not explicitly mentioned).
However, when we look at the study, we can clearly see that it must be buffered coco. Plants would almost certainly fail on unbuffered without specific fertilization (this is likely because calcium and magnesium are drawn from the nutrient solution until the cation exchange capacity is saturated with the double bonds of calcium and magnesium).

As I said, the study shows the same thing I observe:
I manage Potassium:Calcium:Magnesium ratios exactly as one would for DWC, and on Canna Coco Pro, I never see any calcium or magnesium deficiencies.

You don't need to consider the substrate values in practice, the potassium in it is quickly depleted. That’s no reason to add extra calcium until late flowering.

As said: Normal Ca/Mg values and all is good. Tried to copy the coco fertilizer first, but turned out to be bullshit (Undiluted NS).
View attachment 19123744

Knowledge is king!

Runs under your belt teach you first hand knowledge

I have a run or 2 under my belt in COCO DTW.

Criticize my grows all you want because I’m far from a master grower!

Otherwise DrDutch all you are doing is criticizing! I’m from Missouri the show me state. Teach don’t preach! Your elementary cartoons about growing are cute!

Happy New years!

Peace

 

[Orange's Greenhouse]

the specific substrate is not explicitly mentioned

It is. But even if it wasn't they measured the cation content so you can replicate the experiment.
It is unlikely to be buffered due to the high K and low Ca/Mg content.

Plants would almost certainly fail on unbuffered without specific fertilization

You have anything to prove that claim? I mean the paper states the opposite (you do so yourself below).

the cation exchange capacity is saturated with the double bonds of calcium and magnesium

What the fuck is a double bond of calcium? I have never encountered that terminology. If you want to use specific jargon you better explain it. Otherwise stick to the accepted nomenclature.

As I said, the study shows the same thing I observe:
I manage Potassium:Calcium:Magnesium ratios exactly as one would for DWC, and on Canna Coco Pro, I never see any calcium or magnesium deficiencies.

The study saw Ca deficiency. Blossom end rot is characteristic for that. So I don't know what you are on about?
And now you propose using standard fertilizer when before you said coco needs specific fertilizer to prevent complete crop failure.

Tried to copy the coco fertilizer first, but turned out to be bullshit

Did you test their fertilizer content with lab tests or did you just assume that the numbers of the package adequately characterize the content? Because they don't and if you followed them then you didn't replicate the fertilizer.

 

[Ca++]

The K in coco isn't depleted over time. It's release increases over time, as de-composure increases.

As an example, I reuse my coco. I had 2G per meter, split between 8 quart pots. Doing the commercial 18+, so if it were to be depleted, mine would be. At week 6 I removed K from my feed completely. A few days later, after 6 fertigations per day, with 15% runoff, I sent my runoff to be checked. As we know, K in solution is taken within hours, and redistributed. It's not taken on demand, it's hoarded like N. So in my mind the water report was going to list K that must of just come from the coco.
About 200ppm. 6 times a day I watered through, producing 200ppm of K each time. These are astronomical numbers imo.

Ca is double bond, Ca++ or Ca2+ we see written. While K is K+. This is why Ca can push off K. I just got up, so I won't deep dive. I would get it wrong

 

[Dr.Dutch]

Hey, after thinking it over and looking at the study again, I agree with your point—it really does seem like the coco used in the experiment might not have been buffered. The high potassium and low calcium/magnesium ratios in the results strongly support that conclusion. You’re right that the study even shows minimal calcium depletion in the nutrient solution, despite the unbuffered substrate, which is quite interesting.

This makes the case for specialized coco fertilizers, like the ones Canna sells for their pre-washed and buffered coco, even less convincing. If unbuffered coco doesn’t cause massive nutrient imbalances under their conditions, then the claim that you need these specific formulations becomes questionable.

As I mentioned earlier, my attempt to replicate the fertilizers was based on manufacturer-provided data. It’s entirely possible that these claims are just marketing fluff, and the fertilizers for hydro, coco, and soil might not differ as much as they’d like us to believe.

I can confidently say that the fertilizers I use contain exactly what they’re supposed to, and my nutrient mix consistently delivers healthy plants from start to finish in bloom—assuming no other issues arise, of course.

l'm recycling my coco also. Regarding nutrient uptake @Ca++ , I wouldn’t be so certain. While potassium is actively absorbed, it likely doesn’t leave the nutrient solution very quickly, and things look quite different in a substrate. Know what your talking about, Bugbee mentioned this here.

As far as I know, coco decomposes very slowly due to its high lignin content (if I’m remembering that correctly). If the coco is properly buffered, you can consider it an inert substrate—at least that’s my understanding.

The study saw Ca deficiency. Blossom end rot is characteristic for that.

But here I have to ask you if you actually read the study properly
We have a nutrient analysis of the harvested plants, and calcium levels are identical across all substrates. So, if there was a deficiency, it was the same for all and not related to the substrate.

And blossom end rot was higher on rockwool. The disease is very typical for tomatoes, therefore they test it i suppose (though yes, calcium is also important for preventing blossom end rot in cannabis—at least according to Bugbee^^).

So, have a great start to the new year
Peace

PS: And please excuse me if my science English isn’t perfect yet—"it’s not my native language", to say it with the words of my avatar. I’m also not entirely sure if "depletion" was the right word there. GPT helped a bit with the translation, but it doesn’t feel quite right to me either. I’ll take a closer look later at everything I’ve written to make sure it actually makes the sense it’s supposed to. But the explanation with the double bonds was correct from Ca++. I believe the word GPT used for it should be the right one in English

 

[Ca++]

l'm recycling my coco also. Regarding nutrient uptake @Ca++ , I wouldn’t be so certain. While potassium is actively absorbed, it likely doesn’t leave the nutrient solution very quickly, and things look quite different in a substrate. Know what your talking about, Bugbee mentioned this here.

I presume you mean this paper https://www.researchgate.net/public...anagement_in_recirculating_hydroponic_culture
On page two, he says K is removed in a few hours.

Consider this. If the coco offered no K, and I have done dtw 20 odd times with no K in the feed, how much K should be in the runoff. Add to this I have plants in there, that should be taking the K in hours, and it's been days, then how much K should be in there.
I have taken the coco, washed it with no k for days, with a k remover shoved in it, and verified that coco makes K. I didn't need this verification though. I didn't doubt it. I needed to put some actual numbers to how much K was being released.

Unfortunately we can't just stop feeding K, due to our need to suppress the Na. If this were inland coco we could, but we are using Canna. We must keep Na low in the general ratio of things. Which is why we are still adding K to the feed, along with the Ca and Mg, that are meant to be getting rid of K.


I have used the wrong label feeds plenty of times. They are just bottles of stuff. Like ingredients for us to cook with. They can be combined in different ways. Which is handy when you change substrate and have bottles sat around doing nothing. It's the analysis on the side that matters, if you can trust it. The designation of coco/soil/hydro is just a general direction. A coco feed used in rockwool sounds fine to me. The K difference doesn't really effect cannabis, and the higher Ca & Mg is about as different as moving house. It's the pure hydro feeds to watch. The DWC and F&D suited stuff. They can have a much higher EC, biased towards N, that an accumulating substrate with expected dry backs can't accommodate.

Some people buy one bottle, and just use it in everything, for everything. There results might not be equal though.

 

[Dr.Dutch]

I presume you mean this paper

I mean the paper here, where he also explains the different absorption rates.

Principles of Nutrient and Water Management for Indoor Agriculture

Mass balance principles are a cornerstone of efficient fertilizer use and can be utilized to optimize plant nutrition without discarding or leaching solution. Here, we describe the maintenance of closed hydroponic and soilless substrate systems based on mass balance. Water removed by...

www.mdpi.com

The things here are interesting

3. Differential Rates of Nutrient Uptake​

Frequent monitoring of individual nutrients in solution is often recommended, but the need for monitoring can be minimized by deriving a refill solution using the mass balance principles. Monitoring approaches usually attempt to maintain the concentration of each nutrient in solution. However, rapidly growing plants are hungry for nutrients with active uptake. They will continue absorbing nutrients with no sense of when to stop. If the nutrient concentration is maintained at initial levels, the plant will continue absorbing them, sometimes to toxic levels [45]
[...]
Nutrients can be divided into three uptake categories: active, intermediate, and passive (Table 3). Nutrients with active uptake are rapidly removed from solution, and frequent replenishment can result in excessive uptake [48]. Nutrients with passive uptake are taken up at the same rate as water, and their concentrations remain close to their initial level [49]. Nutrients with intermediate uptake can be taken up faster than water but at lower rates than those with active uptake.

There’s something interesting written here, it sounds pretty intense at first.

3.1. Uptake of Nitrate and Ammonium​

N is taken up from solution faster than the sum of all other nutrients [53,54], and it is the only nutrient taken up as both a cation (ammonium, NH4+) and anion (nitrate, NO3−) [55]. The uptake of these two ions alters pH due to the principle of charge balance [33]. NO3− uptake causes hydroxide ions to be released (or protons to be absorbed), which raises the pH. NH4+ uptake releases protons, which lowers the pH. It is possible to stabilize pH by controlling the concentration of these two ions in solution (Figure 3), but NH4+ is taken up 100 to 1000 times faster than NO3− [56]

But then, if you look at the graph here. Even for ammonium, which is absorbed the fastest, it took about 15 days to reach depletion (that's the right word, that's also what I wanted to say regarding potassium), in a DWC system.

Figure 4. pH changes in lettuce grown with 100% nitrate (NO3−, red line) and ample NO3− but excess ammonium (about 0.1 mM ammonium, NH4+, blue line). The system with 100% NO3− did not increase above pH 5.8 because pH was automatically controlled to prevent increasing pH with nitric acid. Neither system had automated control to prevent decreasing pH. The pH in the high-ammonium system started to increase on day 17 after the NH4+ was depleted and uptake was all from NO3−.​

That doesn’t sound like potassium, which is absorbed much more slowly, would be taken up by the plants in Coco within hours.

The effect of the NO3− to NH4+ ratio on pH can be less significant in soilless substrates, because of the buffering capacity of the substrate and increased microbial nitrification of the NH4+.

In soilless substrates, these nutrient interactions are more complex as cations are absorbed and desorbed from the solid phase depending on pH, but these interactions are simplified in hydroponics where nutrients are uniformly distributed, and availability can be rigorously quantified.

Ok, and now I’m completely confused. Just asked GPT about the scientific consensus on coco in agriculture.
And the AI is currently very confident that coco is buffered with potassium.
This aligns with the analysis from the study and your observations.
But also not sure if the AI isn't just hallucinating hear.

Cation Exchange Capacity (CEC) of Coconut Substrate​

The Cation Exchange Capacity (CEC) of coco substrate (cocopeat) is a critical property that influences its effectiveness as a growing medium. Below are the key scientific insights:

---

1. Cation Exchange Capacity (CEC)​

• High CEC: Coco substrate has a relatively high CEC, typically ranging from 20–80 meq/100g. This means it can effectively bind positively charged nutrients (cations) such as potassium (K⁺), calcium (Ca²⁺), and magnesium (Mg²⁺), releasing them slowly for plant uptake.
• Dependence on Quality: The CEC varies depending on the quality and processing of the substrate. Untreated cocopeat may have a lower CEC compared to buffered cocopeat.

---

2. Preference for Specific Cations​

Coco substrate shows varying affinities for different cations, which can affect nutrient balance:

• Strong Affinity for Potassium (K⁺): Coco substrate naturally binds potassium strongly and stores it in high amounts. This can displace other cations like calcium (Ca²⁺) and magnesium (Mg²⁺).
• Weaker Affinity for Calcium (Ca²⁺) and Magnesium (Mg²⁺): These nutrients are less strongly bound and can be displaced by potassium. This may lead to deficiencies if the substrate is not properly buffered.
• Sodium (Na⁺): Raw cocopeat can contain high levels of sodium, which is also strongly bound. Sodium can interfere with the uptake of essential cations, posing a risk to plants.

---

3. Buffering and Pretreatment​

• Why Buffering Matters: To mitigate nutrient imbalances, coco substrate is often chemically treated ("buffered") using calcium chloride (CaCl₂) or calcium nitrate (Ca(NO₃)₂). This displaces excess potassium and sodium.
• Effect of Buffering: Buffered coco substrate has a more balanced cation composition, enhancing the availability of potassium, calcium, and magnesium for plants.

---

4. Impact on Plant Growth​

• Potassium Imbalance: Without buffering, the high potassium levels in coco substrate can inhibit calcium and magnesium uptake in plants (antagonistic effect).
• Nutrient Retention: The high CEC makes coco substrate an effective medium for nutrient storage and gradual release, particularly beneficial in hydroponic systems.

---

Summary​

Coco substrate has a high CEC, making it excellent for storing and releasing cations like potassium, calcium, and magnesium. However, it has a strong affinity for potassium, which can lead to imbalances and deficiencies in other nutrients. Buffered coco substrate reduces these risks, ensuring a more balanced nutrient availability for plants.

Course

Of course, this is something that growers need to avoid and to prevent it from happening the coco substrate is often washed thoroughly to leach excess sodium and chloride. It is then pre-treated with a calcium fertilizer such as calcium nitrate to enhance the potassium-calcium exchange. This process is called buffering and it produces a coco substrate that is not likely to release excess potassium or bind the calcium and magnesium required for plant growth.

How to use Coco Coir as a concept | CANNA Australia

Coco coir is the name given to the natural fibre extracted from coconut husks

www.canna.com.au

But, they want to sell their products.. here it is again.

1. Select the right nutrient product (i.e a specific coco nutrient product) to use on coco substrates. Coco growing media is not like many other soilless substrates such as rockwool which arrive pre sterilised, chemically inert with a low CEC and with a very minimal effect on the composition of the nutrient. Coco contains naturally occurring potassium which since potassium is a major plant nutrient, is considered a bonus; however this needs to be allowed for in the nutritional program of the plants. Coco also has other effects on the composition of the nutrient solution applied and levels of nitrate, phosphate, calcium, magnesium and iron may need to be adjusted to allow for these properties. There are commercial brands of specific `coco nutrient’ formulation products on the market, however it is always a good idea to select both the coco substrate and the coco nutrient of the same brand as it is likely they have been developed to work together and will give the best results. High quality coco products are likely to have been pre-treated and the accompanying coco nutrient will take this into account so that the ratio of elements in the root zone stays as optimal as possible.
   
   

   Growing with COCO | CANNA UK

   Coco or coir is the outside layer of coconut husks (or mesocarp) which consis

   www.canna-uk.com

But the problem is: The data does not confirm it. If it would be so, one could see some differences here.
No significant different nutrient release or content in the plants, and this is a 35 week trail.

But with one thing from the canna hp I would agree.

Because it feels like none of this is helping me in any way, just makes the head spin

 

[Ca++]

It's hard work finding graphs from those monitoring individual levels. Even those selling the equipment, are not offering info packs that show the results we might expect. I would need to see the graph, know the plants, the size of the plants, and the amount of water. Just to get a basic idea of what they did.

I liked the tomato study that looked at the right refill solution. They found in grow, that the top up solution needed it's N and K about doubling. While in fruit, just the K portion of the top up feed needed doubling. This gives some idea of how fast the tomato's were depleting the N and K, over other elements. Without needing to know too many other details.
The suggestion here, is that fruiting toms are not taking N faster than K.
I ran with this through bloom, increasing both about 50% until the last week. I saw no deficiencies of K, at all, which was refreshing. While N was perhaps a bit high, as my base feed is high N to begin with. I was over 200ppm N in a fresh tank, F&D

Results matter more than the science though, and my head is starting to hurt. Lets have a spliff and a coffee, and maybe pick this up again afterwards.

 

[Orange's Greenhouse]

I mean the paper here, where he also explains the different absorption rates.

Principles of Nutrient and Water Management for Indoor Agriculture

Mass balance principles are a cornerstone of efficient fertilizer use and can be utilized to optimize plant nutrition without discarding or leaching solution. Here, we describe the maintenance of closed hydroponic and soilless substrate systems based on mass balance. Water removed by...

www.mdpi.com

The things here are interesting


There’s something interesting written here, it sounds pretty intense at first.


But then, if you look at the graph here. Even for ammonium, which is absorbed the fastest, it took about 15 days to reach depletion (that's the right word, that's also what I wanted to say regarding potassium), in a DWC system.

That doesn’t sound like potassium, which is absorbed much more slowly, would be taken up by the plants in Coco within hours.




Ok, and now I’m completely confused. Just asked GPT about the scientific consensus on coco in agriculture.
And the AI is currently very confident that coco is buffered with potassium.
This aligns with the analysis from the study and your observations.
But also not sure if the AI isn't just hallucinating hear.


Course

But, they want to sell their products.. here it is again.


But the problem is: The data does not confirm it. If it would be so, one could see some differences here.
No significant different nutrient release or content in the plants, and this is a 35 week trail.

View attachment 19124291

View attachment 19124292

But with one thing from the canna hp I would agree.

View attachment 19124294

Because it feels like none of this is helping me in any way, just makes the head spin

Please learn some general chemistry before you talk so much. You are lacking basic understanding of what an ion exchanger does and how it behaves. It would also help you to decide if the chatbot is hallucinating. On the other hand, if you understood the subject you could use a textbook for information and wouldn't rely on a chatbot that has proven time and time again to be useless for such tasks as information retrieval.
The study discussed earlier only started monitoring the nutrient solution in week 4 when the CEC of all substrates is in equilibrium with the nutrient solution. It did not investigate the need for buffering.

 

[Orange's Greenhouse]

It's hard work finding graphs from those monitoring individual levels. Even those selling the equipment, are not offering info packs that show the results we might expect. I would need to see the graph, know the plants, the size of the plants, and the amount of water. Just to get a basic idea of what they did.

I liked the tomato study that looked at the right refill solution. They found in grow, that the top up solution needed it's N and K about doubling. While in fruit, just the K portion of the top up feed needed doubling. This gives some idea of how fast the tomato's were depleting the N and K, over other elements. Without needing to know too many other details.
The suggestion here, is that fruiting toms are not taking N faster than K.
I ran with this through bloom, increasing both about 50% until the last week. I saw no deficiencies of K, at all, which was refreshing. While N was perhaps a bit high, as my base feed is high N to begin with. I was over 200ppm N in a fresh tank, F&D

Results matter more than the science though, and my head is starting to hurt. Lets have a spliff and a coffee, and maybe pick this up again afterwards.

What is depleted in the reservoir might be different than what it requires for optimal productivity. Later on in its life cycle it might still hoover up all N it can find to store it for later but not put it to use, eventually leading to worse performance while it requires the high K it is fertigated with. In a field it makes sense to store what is available at that time but not in a controlled environment.

 

[Ca++]

N toxicity is so common, because they just can't help themselves.
It's a bit like me and this Christmas chocolate mountain I must level.
Other issues are not so widely recognised, but that npk tier along with Mn are worth learning individually (though I haven't)

Many home gardening feeds are just npk, because of their accelerated use. When viewed beside other other components in the soil.

 

[Dr.Dutch]

Please learn some general chemistry before you talk so much. You are lacking basic understanding of what an ion exchanger does and how it behaves. It would also help you to decide if the chatbot is hallucinating. On the other hand, if you understood the subject you could use a textbook for information and wouldn't rely on a chatbot that has proven time and time again to be useless for such tasks as information retrieval.
The study discussed earlier only started monitoring the nutrient solution in week 4 when the CEC of all substrates is in equilibrium with the nutrient solution. It did not investigate the need for buffering.

No problem, see my sig and the scientific motto "I know nothing, I am only evolving," which you are welcome to keep in mind.
In this sense, I also don’t know whether one could perhaps flush and buffer Coco with both Ca/Mg and K. Both could be correct, and I might have only been aware of one so far.

The question here is about the properties of the CEC in Coco. It doesn't behave as straightforwardly as peat, where the exchange capacity uniformly stores and releases all cations (equilibrium between the cations dissolved in water and those bound by the CEC).

May I see your plants, or is this just about proving your theoretical knowledge?

What is depleted in the reservoir might be different than what it requires for optimal productivity. Later on in its life cycle it might still hoover up all N it can find to store it for later but not put it to use, eventually leading to worse performance while it requires the high K it is fertigated with.

How do you come to the conclusion that no nitrogen is needed at the end? Bernstein found a reduced potassium requirement during flowering in her study.

Effect of Potassium (K) Supply on Cannabinoids, Terpenoids and Plant Function in Medical Cannabis

We have demonstrated in previous studies that the essential macro-nutrients nitrogen (N) and phosporous (P) have profound effects on the production of cannabinoids and terpenoids in the cannabis plant. The present study was undertaken to evaluate the hypothesis that potassium (K) supply, which...

www.mdpi.com

Keep nitrogen levels high until the end. It's bro-science/bullshit from manufacturers that we need more PK at the end and no N anymore.

You can also check the data here. It’s clear that there’s more nitrogen and phosphorus in the flowers than in the leaves, while potassium is only minimally higher.
And Bugbee used quite a lot of potassium in his study, but he actually recommends a 20-10-20 NPK (fertilizer ratio) from start to harvest.

https://www.researchgate.net/publication/364347275_Sustainable_Cannabis_Nutrition_Elevated_root-zone_phosphorus_significantly_increases_leachate_P_and_does_not_improve_yield_or_quality

And for the phosphor myth busting also

Frontiers | The Highs and Lows of P Supply in Medical Cannabis: Effects on Cannabinoids, the Ionome, and Morpho-Physiology

Environmental conditions, including the availability of mineral nutrients, affect secondary metabolism in plants. Therefore, growing conditions have signific...

www.frontiersin.org

N toxicity is so common, because they just can't help themselves.

Regarding nitrogen, this is interesting: (Connected to Bugbee, I believe it’s a paper, possibly the thesis of one of his students or something like that).
NH4 causes toxicity, not nitrogen in general.

Nitrogen Nitrogen (N) is a mobile macronutrient with active uptake and usually the most limiting nutrient for plant growth (Miller and Cramer, 2005). In addition to being an integral component for the synthesis of nucleic acids, proteins, enzymes, and chlorophyll, N has also been identified as a signaling molecule in many processes, including shoot and leaf growth, branch formation, and flowering (Lin and Tsay, 2017). Nitrogen is absorbed by roots in the form of nitrate (NO3 - ) or ammonium (NH4 + ) (Luo et al., 2020). Ammonium (NH4 + ) is not stored in plant tissues, and over application has the potential to induce phytotoxicity (Chen et al., 2004). NO3 - does not induce toxicity and plants may hyperaccumulate NO3 - in their tissues (Soltabayeva et al., 2018) and generally, tissue concentrations of NO3 - correlate with rhizosphere NO3 - concentrations (Chen et al., 2004; Devienne-Barret, 2000).

https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1187&context=etd2023

Some people buy one bottle, and just use it in everything, for everything. There results might not be equal though

I mix one tank for all. Mothers, clones, bloom from start to finish: 2-1-2 NPK (fert.), 3:2:1 K:Ca:Mg.
EC between 1.0 and 1.5, and keeping the drain not higher than 1.5. No flushing at all, just some drain so I can measure it (KISS according to Bugbee.)
2 weeks left here. I will just give them plain water the last days so that the ec is not to high in the substate for the next plants (I assume that maybe the decomposing of the roots could release some nuts over the storage time).

And some six month old mothers. Also in 3.5l Coco/Perlit, works fine too

Peace

 

[Ca++]

NO3 is the best N for us, but if we don't also use NH4, we get water regulation problems. Seen first pooling in the leaves, with effects like waves across the sea. Older leaves show this accumilation first. Often being a bit large and droopy, and very possibly in lower air movement areas, like against the tent wall.
NH4 is useful to about 5% of the total N supplied. After which downward trends occur. By about 30% half the bud is missing, and 40% brings death.
I think the plant will take it in, but then just sits on it for ages. Does nothing with it, when it should of taken NO3 and got busy. Though I'm guessing.


Your plants look nice enough to speak for themselves.
I think the change in feeds going into flower is useful. Mainly I think the plant wants a drop in N, to steer it towards finishing. There is no need to continue with this though, once the corner has been turned. Like with Jacks cannabis, we can use the grow again after the transition. Not every grow wants steering quickly through transition though. It's just an option. In today's grow, I'm extending transition.

 

[Ca++]

That doesn’t sound like potassium, which is absorbed much more slowly, would be taken up by the plants in Coco within hours.

Search that page for "Nutrients were added each day in the refill solution with an EC of 0.9 mS cm−1, but these nutrients were removed within one day" Which is some way down, below fig5
When you add to all together, they seem to be showing the mass balance approach, where all the feed is in the tank on day one, and by the end of the crop all the feed is in the plants. Even when little is left in the tank, the plants is still getting enough. Then, just as it all seems clear, they chuck a spanner in the gears, with daily top-ups. We can't see these on a graph with just one daily plot. We want to see a day split into 24, not as a whole.
These graphs don't show what happens over the course of a day, but they do tell us they added feed, which was all gone by the time they measure again.



I have to look at my Potassium Nitrate additions again. I have read studies on N, P and your K one fully today. Each speak of reduced cannabinoids. The K study comes last, so reflects upon this and the idea of carbon or feed. The carbon/nutrient balance hypothesis. Which might be the biggest awakening I have had all this year.