Machine feeds

[Douglas.Curtis]

One of the traits of a 'Dynamic Accumulator' type of plant, like cannabis, is the way they 'look fine' while quietly locking excess molecules and elements to cell walls. What is fixed to the cell walls does not 'flush out.' So IME the smoke ends up a higher temp, starts to taste like burnt stuff within a few hits, and leaves a thicker ash with weight to it. I believe you'll readily see this at the end of this run.

When your errors are underfeeding, the plant generally shows it right away. No silent quality killing going on in the background like overfeeding. I'll cram a bowl super tight with flower, poke a tiny air hole, smoke it, and have a super lightweight ash fall out with a light puff or tap. The last exhale of the bowl should be tasty, and have almost zero "burnt plant/stuff" taste to it. Cool temp, soft feeling, resin rich flavors and aromas till the last hit.

The full pH swing is what allows this at 1.5EC and lower. Each element has a different pH range where it is readily absorbed by the plant. Providing this full pH cycle means the plant can easily absorb what it wants at each stage. With roots-in hydros, like DWC and NFT, the pH swing should happen in approximately 7 days at the beginning of a run, and this can be adjusted through nutrient solution volume. Roots-out hydros, basically any set up where the roots are not constantly in contact with the nute solution, have this same pH swing in the rez, and also a smaller pH swing which happens between irrigation cycles.

I use nutrient dosing for top and bottom end pH control, and let the plants do the main work for me.
This Only Works Perfectly with R/O or similar water (0-12ppm)
Fill rez, add nutes to starting EC, pH up with a calcium carbonate product to lowest healthy pH.
Top off to same level every day with pure r/o and take your readings.
As the plants use the nutes the pH rises.
When pH hits top end of healthy range, add nutes back to starting EC. pH will automagically be back where it was when you started the rez.

Lather, rinse, repeat till physical flower bulking quits, then I use lowered EC to maintain high transpiration through oil production til harvest. 5 days from harvest my rez is replaced with plain r/o.

 

[Hiddenjems]

I run flood and drain pebbles in containers.

I did a test grow in a 4x4 tent with 450w of LEDs and a cut I had been running under hps for around 2 years. All I did was keep the temps 10* warmer than my hps rooms and it turned out perfect.

I started my feed at 2 ec and upped it gradually to 2.6 at week 6, then back down to 2.0 until finish. I didn’t see and abnormal peaks or drops in ec.

I think you’re right and you’re just maxing out your transpiration.

 

[Douglas.Curtis]

Right, with the transpiration maxxed out the low nutrient level ends up delivering a lot of nutes anyway.

 

[Ca++]

One of the traits of a 'Dynamic Accumulator' type of plant, like cannabis, is the way they 'look fine' while quietly locking excess molecules and elements to cell walls. What is fixed to the cell walls does not 'flush out.' So IME the smoke ends up a higher temp, starts to taste like burnt stuff within a few hits, and leaves a thicker ash with weight to it. I believe you'll readily see this at the end of this run.

When your errors are underfeeding, the plant generally shows it right away. No silent quality killing going on in the background like overfeeding. I'll cram a bowl super tight with flower, poke a tiny air hole, smoke it, and have a super lightweight ash fall out with a light puff or tap. The last exhale of the bowl should be tasty, and have almost zero "burnt plant/stuff" taste to it. Cool temp, soft feeling, resin rich flavors and aromas till the last hit.

The full pH swing is what allows this at 1.5EC and lower. Each element has a different pH range where it is readily absorbed by the plant. Providing this full pH cycle means the plant can easily absorb what it wants at each stage. With roots-in hydros, like DWC and NFT, the pH swing should happen in approximately 7 days at the beginning of a run, and this can be adjusted through nutrient solution volume. Roots-out hydros, basically any set up where the roots are not constantly in contact with the nute solution, have this same pH swing in the rez, and also a smaller pH swing which happens between irrigation cycles.

I use nutrient dosing for top and bottom end pH control, and let the plants do the main work for me.
This Only Works Perfectly with R/O or similar water (0-12ppm)
Fill rez, add nutes to starting EC, pH up with a calcium carbonate product to lowest healthy pH.
Top off to same level every day with pure r/o and take your readings.
As the plants use the nutes the pH rises.
When pH hits top end of healthy range, add nutes back to starting EC. pH will automagically be back where it was when you started the rez.

Lather, rinse, repeat till physical flower bulking quits, then I use lowered EC to maintain high transpiration through oil production til harvest. 5 days from harvest my rez is replaced with plain r/o.

My P is staying under 60ppm. This is less than half of what biobizz bloom gives in the final weeks, and they expect you to also add boosters. Further increasing the P. I use biobizz as an example, as it's to hand. It's by no means the highest.
P gives the chemical factory taste, and hard black ash. I'm not going heavy on it. Contrary to what you were saying, high temps give a more complete burn. The higher the temp, the more stuff will burn. It's logical really. Leading to a cleaner ash. I'm heavy on the K, which increases burn temps. It's the basis of gunpowder, as it helps things doped with it, to combust faster. The tobacco industry can offer advice here. They add various things to get that burn temp high enough for the white ash we expect.
It is of course difficult to say much, without actual lab tests being available to me. It's the amount the bottle says though, so the best place to start. The only deficiency seen has been K. Now fixed, but I will reduce that extra K mid bloom. I have been using their coco feeds of late, and needed to go 50% over bottle advice, so it didn't seem wise to try a lower dose of the hydro feed, than advised. Though I have in the past, before LED.


I get a pH swing, but not by design. The only official verdict I have seen, is that a constant pH is better. We work in a range where everything is available. Our feeds formulated, so that anything a little harder to get, is more abundant. The big stuff that can be relocated, can be taken in a few hours, to last a couple of days. So swings are not a problem. It just stores them while it can, then moves them about internally. The small stuff that can't be relocated, is where problems may occur. A low pH can increase the abundance of some to toxic levels, and these can't later be moved around, so as the pH becomes unfavourable to them, the new growth goes from high supply, to low supply. As they are not mobile. The more plastics we use in our systems, the more likely a toxicity is. As an example, healthy looking plants have shown 10x more Mo in tissue sampling, than was added to the tank. The Mo having come from plastics. Mn Cu Zn, they all leach from plastics, and give the plants more than we did. This isn't bad plastics, it's the right stuff. These metals are needed to keep the plastic more homologous. They are emulsifiers. A guy hand feeding soil in pots, has a lot less exposure than a recirc guy with floppy tanks and hoses. Who might see real problems as low as pH5.5
I'm not sure what you are reading, with these 7 day long pH swings. To me, it just sounds like days of low expose to elements that can't be relocated. Then days of excessive exposure. Individual leaf tissue analysis would be interesting. It can't be done though.

I might get the RO filter out again at some point. My build has been done with the pipes in place. It's great to just top up, and everything is back where it was, uneffected. Though in need of N and K to rebalance there higher depletion, if you want to get really close to where you were.
I was just reading of a study group making there tank at 1.5mM K, then using 4.5mM K as the top up. To average 0.5mM K. Yes, 3x more K in the top up. Toms, not Canna, but it's interesting. Other studies are talking of the top-up EC commonly falling to 25% of the tanks target EC. Which is perhaps where I'm heading. You will be lower, with your wue.

I do have an idea what is going on, but I'm happy you feel your green is the best, and I must be doing something wrong. It's a pitty we are unlikely to ever put it to the test, but every grow is certainly different, and the further we stray from the path, the more new info we can learn. I don't think I will be reducing my wue efficiency so drastically though, as them terps are water soluble. I imagine your room smells nice.

 

[Absorber]

EC3 is very high for me. I'm back to hydro for the first time in years, and was surprised to see the bottle dosing come out so high. Triple checked though, and not with the same calibration solution. Decades ago it was lower, and through my own observations, I was running at 1.6. However, that pushed up past 2.4 the moment I went LED. It's all a bit sketchy looking back, hence doing a run with bottle dose this time. I need to set a benchmark. They do look fine though, except some low K, which I have resolved with this Pot-nit. So the 3.0 probably isn't really high.
It's interesting to hear you top-off with RO, and presume that's not with feed. A sign feed use is dropping a lot through bloom.
My wue is very different, yes. I'm using perhaps 6L per meter, and don't expect a 4x4 would pass 3G a day. Though I have seen 10L a meter before. At 3G beside your 5G, I should be at a higher EC to provide as much food as you do. It is a difficult comparison though, as you say

I found when my ppm went up ( from 1200ppm) plants were taking up more water so i lowered my ppm to 600 during flower and plants started taking up water and nutrients again, dropping level of resevoir but the ppm stayed same . And grew huge cola's at that nutrient strength.
I now run at 500-550ppm in veg and 600-650ppm in flower .
I use Cyco 2 part veg 2 part flower nutrients

 

[Ca++]

Got me checking the bottle. It says the dose I'm using, but gives an expectation of 1.5 - 2.2 (add more if needed)
Hmm. Odd.
The coco and soil say about the same, but the hydro does have about 50% more NPK listed. It doesn't add up.

I suspect I have got this wrong. I have a pair of meters, giving different results. One must be broken. Then I have a tank computer, which I have never calibrated, but does agree with one of the normal meters. This is a 2 onto 1 argument. It might be the 1, who is right. However, both normal meters have been back in the calibration solution, and it sure looks like the 1 meter is broke. Maybe the solution is? It's mixed powder, kept a few weeks in the fridge. I must consider the least likely answer, could be right.
I do have fresh bottled fluid EC calibration solutions, but had decided not to cal the computer. Not for EC or pH. The numbers are not usually something I share anyway. They are just for me to replicate. Also, the computer is Chinese, so I can't work it anyway lol

 

[Orange's Greenhouse]

hard black ash. I'm not going heavy on it. Contrary to what you were saying, high temps give a more complete burn. The higher the temp, the more stuff will burn. It's logical really. Leading to a cleaner ash. I'm heavy on the K, which increases burn temps. It's the basis of gunpowder, as it helps things doped with it, to combust faster. The tobacco industry can offer advice here.

Hard black ash means that carbon is left. Increasing temperature leads to complete combustion thus white, soft ash.

Potassium does not increase the temp. It is just additional weight that absorbs heat. The potassium in gun powder is potassium nitrate (the fertilizer) and the nitrate component is an oxidizer that increases the burn temperature. But there is no significant amount of nitrate in plants so that doesn't do anything.
The most (only) important factors leading to white ash is water content. The more water in the flower, the lower the temperature. Heating and evaporating water is a heat sink.

Something else that can be done is add white salts (eg lime) post harvest. That doesn't influence the taste and can't be overdone (heatsinking) but increases ash volume

Fertility during growth is not important.

 

[Douglas.Curtis]

Uhh... high temps are definitely not necessary for a white and lightweight ash. Most people have a difficult time 'feeling' they actually took a hit, the smoke is so cool and soft. Literally surprised at the huge volume of smoke they exhale, even though they could not feel it in their lungs.

Terps and cannabinoids are greatly assisted in their formation by enzymes. Enzymes create different molecules depending on hydration, temps and pH. So steady pH, steady hydration levels and steady temps make for significantly less complex terps/cannabinoids.

7 days at the beginning of flower. As flowering progresses this swing shortens. My ash is proof to me there isn't anything getting loaded up in my plants.

 

[Orange's Greenhouse]

Terps and cannabinoids are greatly assisted in their formation by enzymes. Enzymes create different molecules depending on hydration, temps and pH. So steady pH, steady hydration levels and steady temps make for significantly less complex terps/cannabinoids.

Please pick up a molecular biology textbook before you spread more of this nonsense.

 

[Douglas.Curtis]

Please pick up a molecular biology textbook before you spread more of this nonsense.

My apologies, temperature changes the speed of the reactions.

The rest is accurate, as you should know if you've studied molecular biology. I've studied enzymes and they do indeed create slightly different terpene/cannabinoid outputs from the same precursors, when hydration and pH changes occur. I'd link the studies but I do not track my history.

Yes, enzymes can produce multiple types of similar molecules as pH and hydration fluctuate. Here's how:

1. **Enzyme Specificity**: Many enzymes can act on different substrates or produce varying products depending on the specific conditions. For example, a terpene synthase may produce different terpenes based on substrate availability and environmental conditions.

2. **pH Effects**: Fluctuating pH levels can alter the ionization states of substrates and enzymes, affecting the enzymatic activity and potentially leading to the formation of different end products.

3. **Hydration Levels**: Changes in hydration can influence enzyme conformation and activity, which may shift the balance of products formed. For instance, some enzymes might favor the production of certain metabolites in high hydration environments while shifting to others under drier conditions.

4. **Metabolic Pathway Interactions**: Enzymes involved in metabolic pathways can compete for substrates. Variations in pH and hydration can shift the equilibrium between these pathways, resulting in different products.

In summary, fluctuations in pH and hydration can lead to the production of multiple related molecules by influencing enzyme activity and metabolic pathways.

Yup... that's what I remember, all typed out in a flash.

 

[Ca++]

Hard black ash means that carbon is left. Increasing temperature leads to complete combustion thus white, soft ash.

Potassium does not increase the temp. It is just additional weight that absorbs heat. The potassium in gun powder is potassium nitrate (the fertilizer) and the nitrate component is an oxidizer that increases the burn temperature. But there is no significant amount of nitrate in plants so that doesn't do anything.
The most (only) important factors leading to white ash is water content. The more water in the flower, the lower the temperature. Heating and evaporating water is a heat sink.

Something else that can be done is add white salts (eg lime) post harvest. That doesn't influence the taste and can't be overdone (heatsinking) but increases ash volume

Fertility during growth is not important.

Have you seen excess K in bud. It's like a sparkler. White hot bits spitting out. Nice white ash left.
I think it was probably an early magazine that put the name to it, so impossible to find my source now. I have looked to the tobacco industry for confirmation though, when this has come up before. 15 mins found nothing but pay wall documents today though. I can offer nothing, but a strong suspicion.

The N for explosives, yes. Pot-nit sales are regulated here, for that reason. I got a dud warning, that overrode reality for a couple of weeks since I bought some. I can't even get Nitric acid at anything stronger than my mouthwash these days. Thanks for clearing that up.


I got a water use number today. In 24h, at day 18, I used 7.5L+ per meter. Though that's imprecise, as I'm measuring the walls of a floppy tank. We could call it 3G per 4x4, under typical conditions. I would say that's drinking well. It's a terrible wue of around a gram. Casting some light on my EC. The last few days the top-up has only been tap with half the N and K dose of if I mixed a full feed. So N K Ca and little else. No sign of mobile deficiencies. Though I must be close. I need to stop that though, and find the right daily feed, to give consistently. To run the tank longer between changes. I will keep doing changes though, until I get a water report regarding the accumulation of plastic products. Our feeds keep some of these low, because of dangers to cattle. While China still send us plastics that use metals that are actually banned. Lead being a typical one, and I have a flexi-tank. I must get a water report from my tank, to understand the frequency at which it must be changed. To remove these products, that 99% of us probably don't know we are adding

6.8% Lead. Thanks Home Depot. 20ppb lead in the water from that one, with 15ppb being the immediate 'take action' level for drinking water. No safe level is given. If we get 20ppb with a single pass, how many passes before we just chuck our crop away? Lets say you just fill with this hose. How much 20ppd water goes through your plants. Few gallons a day? Add it up.
This is an aspect of tank changing for clean cannabis, that many of us are just not looking at. A water sample is £30 here, with Lead and Phalates being additional charges, outside the scope of a standard feed check. I must confess, I have not tested for lead before, but do select products the best I can. PVC free hose linings, suited to potable water delivery, is a must. But that is just scratching the surface. We should test for problems, because manufacturers will lie. Often using recycled plastics, so they can't actually say from day to day, what is going in their products. We have a pinned thread about a hose killing plants. It's not always so obvious.

 

[Orange's Greenhouse]

My apologies, temperature changes the speed of the reactions.

The rest is accurate, as you should know if you've studied molecular biology. I've studied enzymes and they do indeed create slightly different terpene/cannabinoid outputs from the same precursors, when hydration and pH changes occur. I'd link the studies but I do not track my history.

No, not at all. If you've went to university then you missed the most important part: graduating.

A specific enzyme catalyses a specific reaction. If different substrates are available different products are made.
pH, temperature, "hydration level" all sound very sciency but the enzyme is not exposed to changing conditions. The intracompartmental conditions are important and they are stable. If you change these conditions in vitro the turnover rate changes until it stops working all together.
It doesn't matter what is in the rootzone. If that were the case the whole plant would look wildly different because *all* growth processes were influenced. And we know what happens if we only add a little PGR.

And that ChatGPT stuff doesn't mean anything. It is gibberish.

 

[Douglas.Curtis]

Yeah, quit chasing heat for a white ash and you'll be much happier in the long run. That.... and using tap water makes good cannabis so much more involved to grow right. With r/o it's always so close to the same it's easy. Season by season (which changes your tap content) and year by year. (Edit: With tap, any advice given about pH from your grow is anywhere from slightly to completely wrong for someone else's tap water. Sometimes even growers less than a mile away from you will have a different chemical composition).

Everyone is wrong about something lol, thanks for clearing up the enzymes.
(Edit: WOW... looking over studies on root zone and plant pH. Saying root zone pH does not affect plant pH is unbelievably ignorant. Good job!)

 

[Ca++]

Oh, I'm not chasing heat. I was looking at my feed composition, in regard to your expectation my ash was going to be thick and heavy. I'm actually a little concerned that my high K use, will take things the other way. Though perhaps unnecessarily, if Mr Orange's conflicting post is right. Which it might well be, he's obviously a knowledgeable guy.

I'm more concerned about changing feed profiles, due to few tank changes. A bad burn might be easier to notice, but their is solid evidence regarding the accumulation of plastic products. From leaf and tank sampling. The cost of a few tank changes, seems like a good way of resetting the levels. Also leaving me able to experiment with additional elements, without getting totally out of wack by the end. All this blind testing with Pot-nit could be heading anywhere. Though, without tank changes, I would be doing no better.
The mass balance ideas are still teething. We can't add all our feed at the beginning, then just water. Some aspects of our feed could put up with that. Even getting greater over time, as plastics supply more. Our mobiles would be taken until toxicity was seen in a day or two. They are elements the plant will try and stock up on. They are depleted from the tank, faster than the plant actually uses them. This is why they are spoon fed some things, over time. N and K being the one's to really look at.

My plants are going fcuking mental. I bust them all down just a few days ago, and yesterday they were all back up, and one was even inside the HID reflector. From the moment I started this pot-nit, they have been going nuts. I also increased from 4 to 5 floods during the lights on period though, which is a greater feed supply anyway. So I can't call it. It's also my first time in F&D for.. maybe 20 years? but something is very different. Too jungle to show though. Tarzan is swinging about, and at the top are ewoks sunbathing on platforms. Main heads taken out with scissors, and LED panels holding down others. It's like some swapped my cuts for a haze.

 

[Douglas.Curtis]

Yes, nitrogen definitely increases plant growth. I have a great distaste for the fluffier flowers it produces, so if the P is keeping things denser than straight N would at this stage in flower, kudos.

You put a significant amount more work into what you're doing there than I do. Hope it all works out. I'm unsubbing so's not to clutter it up.

 

[Ca++]

I wonder if I should be topping up Mg. That table was for tom's and canna likes Mg. While I'm pushing it out, by topping my recirc res with hard water, and offering more K.
Near the 600 I can see it's lacking, but the lights too low and torching them anyway.

I'm mid bloom and starting to lower N now. So 25% extra N, but the K still increased 50% in the top-up. I have seen some old leaves burn through accumulation, so reduced the ec3 down to about 2.7 and I'm not letting it ride up to 3.5 again. I may reduce my base further, then bring up the PK again, to leave the N lower. I have over 200ppm N, when I tank change. Which is really bloody high. I can't make up a fresh tank like that again.
The Pot-nit is good I think. By now I would of usually seen some K signs, but nothing. I'm just thinking logically, that Mg could need attending to.

My feed says it has Mg, but not how much. It bugs me. However, I have now found it doesn't need shaking. Least they claim so. They also says it's clear though, when it's black with soil acids. Perhaps the GT.AU site isn't using the same formulations.

 

[Orange's Greenhouse]

My feed says it has Mg, but not how much.

I don't know where you're located but in the EU and US the numbers on fertilizers are guaranteed minimums. It has at least this much, maybe (substantially) more.
If it doesn't have a number attached to an element it could be 0 in your particular batch.

 

[Ca++]

I don't know where you're located but in the EU and US the numbers on fertilizers are guaranteed minimums. It has at least this much, maybe (substantially) more.
If it doesn't have a number attached to an element it could be 0 in your particular batch.

Yeah, it's kind of odd. It says on the front 'with Mg and humic acids' like they are a bonus. The label lists everything else, but Mg. I once found a document online, that spoke of minimum levels, before listing was needed. Which suggests my feeds Mg is so low, they needn't report it. I have spent hours looking at the EU labeling requirements though, and can't see it again. Mg issues are never far away, but if I try and bump it 15ppm for the duration, it seems a bit much. I have had the runoff tested, and it suggested fair levels. I may need to have the feed tested for myself.
Growth Technologies Ionic (but all of their feeds seem to share this oversight)

 

[Ca++]

I have my feed vessel sorted. A 500ml car syringe. Just a normal syringe, except the bottom isn't flat, it's a bowl shape, and the spigot is a push-fit fitting, which gives a good secure attachment to the pipe that comes with them. 200 500 and 1500ml are the standard sizes. As I'm topping up about 25ml a day, the 500 will give me a couple of weeks comfortably.

Obviously the plunger comes out, like using a bodum coffee thing for oil. You do know about that right? The bodum coffee thing uses a pyrex lab beaker, with a handle around it. Then a top, just right for gas cans.