Deficiency in...?

[stayrange]

Some elements such as nitrogen and phosphorous are absorbed by active transport mechanisms that arr more efficient than the passive uptake of eg calcium that is mostly controlled by transpiration. That results in accumulation of calcium in the reservoir and salt stress.

View attachment 5394173
Yep.

I think this is the answer that I was looking for. Too much Ca towards the end of the bucket, no control via passive transport.

And I wish you all would try harder to dial in nutes, stop wasting the planet's resources. Go on, ask me if I filter my city water.

You guys do you, but around here, until tips begin to burn... PPM and PAR go up. I'll fix an 'excess' with more, I'll fix a 'deficiency' with more.

 

[ec121]

And I wish you all would try harder to dial in nutes, stop wasting the planet's resources. Go on, ask me if I filter my city water.

You guys do you, but around here, until tips begin to burn... PPM and PAR go up. I'll fix an 'excess' with more, I'll fix a 'deficiency' with more.

Plants can be trained to accept a high EC by gradually increasing the EC, but this also makes osmosis harder for the plant.

The plant has water inside the roots and the plant has water outside the roots. When the water outside of the roots (i.e., the reservoir) has a high EC, the plant has to produce sugars so that the concentration of dissolved solids inside the roots is higher than the concentration of dissolved solids outside the roots in order for osmosis to take place.

In other words, the plant can't get water if the concentration of sugars in the roots are lower than the concentration of salts in the reservoir. If the EC goes up too quickly, then it can actually pull water from out of the roots through osmosis.

If you keep increasing the EC, the plant has to manufacture more and more sugars for water to flow into the roots. When it does this, it's expending energy on producing sugars.

Some of us prefer to keep the EC in the range the plant is expecting so that it will expend it's energy on growth and not sugars, but you do you boo.

 

[stayrange]

The plant has water inside the roots and the plant has water outside the roots. When the water outside of the roots (i.e., the reservoir) has a high EC, the plant has to produce sugars so that the concentration of dissolved solids inside the roots is higher than the concentration of dissolved solids outside the roots in order for osmosis to take place.

...

If you keep increasing the EC, the plant has to manufacture more and more sugars for water to flow into the roots. When it does this, it's expending energy on producing sugars.

Really great information - and I'm hearing that because of this need to regulate osmosis, the plant may grow faster with less nutes.

But do these sugars just disappear into thin air after the plant has adjusted? What's bad about more sugar when it comes time to resorb? How does it affect the yield? I plan to starve the ladies down to 500 PPM to trigger this during ripening.

 

[Drop That Sound]

What scale is your TDS meter anyway?

 

[BongerChonger]

Is this iron?

View attachment 5393870

1000 PAR, 1500 PPM, 5.65 pH DWC

Visually, yes, it could be Iron deficiency.
But...
At that pH Iron should be plenty available. Also, iron's only needed in very small amounts, your nutrient more than likely has ample already.
Indicating, you're dealing with lockout from too much of something else.

I wouldn't ever go over 2.4EC to be safe. Plants really don't need any more than that. You're right at the limit already and a touch over depending on the scale you're using.
Plants can thrive with a lot less.

There's a chance it's pH related also, like calcium or sulphur being less available at 5.65.
Add this to a high EC and it just makes things worse off.
I'd try bumping it up to pH 6.

Then, you're running lots of PAR too...that will just exacerbate things more.

"1000 PAR, 1500ppm, 5.65 pH" <<< that's your problem, right there!

 

[stayrange]

What scale is your TDS meter anyway?

Reading 1360 PPM on the 500 scale which would translate to (1360/500 = ) 2.7 EC.

 

[stayrange]

Visually, yes, it could be Iron deficiency.
But...
At that pH Iron should be plenty available.

I'd try bumping it up to pH 6.

But that would make iron less available, and we've confirmed that its availability is the issue (regardless of why)? https://www.canr.msu.edu/uploads/images/Plant Ag/SoilTesting_Fig1.jpg

Rather than just the pH, what about the individual elements creating that pH (that compete for absorption)? Increased levels of Ca, Mn, Cu, P, Zn can be responsible. https://www.canr.msu.edu/uploads/images/Plant Ag/SoilTesting_Fig2.jpg

I'm targeting the average numbers on this (500 PPM) chart https://zombiegardens.com/indoor-gardening-basics/cannabis-nutrient-ratios/

While most are spot on, Zinc is over double. https://cdn11.bigcommerce.com/s-dund4ckhpz/product_images/uploaded_images/zinc.jpg I'll have to find a separate iron supplement :/

 

[stayrange]

Looks like I could also make Fe more available by increasing K. And I'm reading that molybdenum reduces the availability of iron as well, but not seeing it on any of the charts. https://dutch-passion.com/img/cms/Blogs/Molybdenum.jpg . Mo is super high. Based on the periodic table, we'd expect it to lock out the same things that other transition metals would (they antagonize iron).

 

[stayrange]

Then, you're running lots of PAR too...that will just exacerbate things more.

Rather, running lots of PAR without PPM is the problem. Can't have one without the other. They must go up together. Balance the reaction.

 

[BongerChonger]

But that would make iron less available, and we've confirmed that its availability is the issue (regardless of why)? https://www.canr.msu.edu/uploads/images/Plant Ag/SoilTesting_Fig1.jpg

Point I'm trying to make is, visually, how can you be sure it isn't Calcium or Sulphur deficiency symptoms showing, not Iron for example? They all exhibit interveinal chlorosis and yellowing in newer growth when deficient or locked out.

Rather than just the pH, what about the individual elements creating that pH (that compete for absorption)? Increased levels of Ca, Mn, Cu, P, Zn can be responsible. https://www.canr.msu.edu/uploads/images/Plant Ag/SoilTesting_Fig2.jpg

You're running 2.7EC. Using the chart, how can you be sure it isn't a mobile element like phosphorus locking iron or calcium out?
High phosphorus levels in most nutrient mixes.
Couple that with a very high EC and you have a recipe for lockout.
It's almost always one of the NPK's that's the culprit, they're the most mobile and most abundant.

While most are spot on, Zinc is over double. https://cdn11.bigcommerce.com/s-dund4ckhpz/product_images/uploaded_images/zinc.jpg I'll have to find a separate iron supplement :/

If that's true, why add iron, not take zinc away?

Rather, running lots of PAR without PPM is the problem. Can't have one without the other. They must go up together. Balance the reaction.

If you have a present problem and you're blasting it with heaps light, then it's more demand on the plant, potentially exacerbating any present problems.
1000 PAR is a lot!
Again, right at the limit.

Reading 1360 PPM on the 500 scale which would translate to (1360/500 = ) 2.7 EC.

That's very high!
Likely too high, causing lockout.
Simple as that.

and we've confirmed that its availability is the issue (regardless of why)? https://www.canr.msu.edu/uploads/images/Plant Ag/SoilTesting_Fig1.jpg

Not at that pH and EC you haven't, not iron.
Iron's one of the last things to consider.

While most are spot on, Zinc is over double. https://cdn11.bigcommerce.com/s-dund4ckhpz/product_images/uploaded_images/zinc.jpg I'll have to find a separate iron supplement :/

If your ratios are spot on, then why not take zinc away?
If your ratios are spot on, just add more plain water, lower EC.

 

[stayrange]

Point I'm trying to make is, visually, how can you be sure it isn't Calcium or Sulphur deficiency symptoms showing, not Iron for example? They all exhibit interveinal chlorosis and yellowing in newer growth when deficient or locked out.

They exhibit quite a different quality of interveinal chlorosis.

If your ratios are spot on, then why not take zinc away?

I'll just grab it out of the bucket real quick hold my beer =D

My iron and zinc come mixed 1:1, need another iron source.

 

[BongerChonger]

They exhibit quite a different quality of interveinal chlorosis.

Wouldn't be so sure of yourself, they can look pretty similar.

They exhibit quite a different quality of interveinal chlorosis.



I'll just grab it out of the bucket real quick hold my beer =D

My iron and zinc come mixed 1:1, need another iron source.

So you're still thinking it's deficiency?
Well you do you pal.
Try Iron chelate.

 

[stayrange]

Deficiency in the plant... or deficiency in the water? Which matters?

I'll overdose the water to adjust ratios, compensating for minerals that I just can't remove - whether they came from the city tap or from a cheap nutrient that I've selected for economic reasons.

This blend is already performing better than GH Maxigrow side by side during veg and this is an early attempt using cheap nutes (which are difficult vectors with which to produce an optimally balanced solution given their composition of multiple elements), many of which I already had on hand. While feeding to the last gallon.

I appreciate all the help and discussion, but my goals do include: city water, drinking 80% of the solution.

 

[ec121]

Really great information - and I'm hearing that because of this need to regulate osmosis, the plant may grow faster with less nutes.

But do these sugars just disappear into thin air after the plant has adjusted? What's bad about more sugar when it comes time to resorb? How does it affect the yield? I plan to starve the ladies down to 500 PPM to trigger this during ripening.

Excess sugars are converted to starch and stored by the plant to be converted back to sugar for energy (e.g., at night when photosynthesis isn't possible). Plants with excessive starch reserves do not grow as fast.

I appreciate all the help and discussion, but my goals do include: city water, drinking 80% of the solution.

Plants take up water and nutrients separately. It's not like the roots are sucking in nutrient water like through a straw. They use different mechanisms for water and nutrients and under normal conditions take up water quicker than nutrients, which is one reason why the EC in a res will fluctuate.

So it's cool that you want to do things your way, ways that others have tried in the past, but when it has a deleterious effect on your plants, don't be surprised or upset about it.

 

[stayrange]

New bucket, 2.5 EC (from 2.7). Zn still high due to iron source. Reduced Ca, Mg. Increased NPK, Cu, Bo.

Still one plant showing significant interveinal chlorosis.

From top to bottom, I've circled symptoms of iron, copper, boron deficiencies.

Plants with excessive starch reserves do not grow as fast.

No wonder my roots are so big!

 

[ec121]

No wonder my roots are so big!

Where's your control plant?

 

[stayrange]

Where's your control plant?

Do you mean the plant with commercial nutes (Maxigrow in this case) to compare with? These aren't clones but F1 seeds. I moved off the GH after 1 week in all buckets. Just rooted some clones of the fastest growing female in my conditions. Can test them next. Pic at 10 days in the aerocloner with aloe, 200 PPM Maxigrow, fulvic acid.

 

[stayrange]

Excess sugars are converted to starch and stored by the plant to be converted back to sugar for energy (e.g., at night when photosynthesis isn't possible).

And I veg 24/0 which means those roots just keep on growing! How much of this will be available to resorb during flower at night?

 

[stayrange]

How much of this will be available to resorb during flower at night?

https://www.cell.com/current-biology/pdf/S0960-9822(22)01125-3.pdf

TLDR:

They use it when they need it... "...retrieved to support metabolism and anabolic reactions in times of need" and this need "varies widely depending on the biological context" (Zeeman, 2022).

Besides feeding at night, the starch reserves provide extra energy during periods of stress, and "in reproduction (roles in nectar secretion, flower iridescence and pollen viability" (Zeeman).

The authors then compare tobacco plants with a mutant who is unable to produce starch reserves. When days were shortened (nights lengthened) the plants without reserves suffered slower growth (Zeeman).

And conclude that they have just begun to answer the question "What is the link between starch accumulation (or its absence) and photosynthesis" (Zeeman).