Calcium deficiency in high pressure aeroponics

[endorflight]

Hello,
iam back with my second HPA grow and currently trying to deal with what i think is a calcium deficiency.

There are two plants of Philosopher Seeds Chiquita Bannana grown from seeds. The plants are 10 weeks old and got flipped a few days ago.

One of the two plants (left) is showing little of these symptoms from the beginning. The other plant was not affected at all, however, meanwhile it also has two tiny rust spots.

Nutrients:

• RO Water
• Advanced Nutrients Silica 1ml/l (50% Strength)
• Canna CalMag 0,5ml/l (100% Strength)
• Advanced Nutrients Grow/Micro/Bloom 1,5ml/l (50% Strength)
• Purolyt (HOCL) 1ml/l (100% Strength)

Final solution comes out around 1000µS/cm

About two weeks ago i went too high with the Nutrients >1500µS/cm and the roots started to brown. I dailed back and since then i have incredible white and fuzzy root growth. Also i switched from AN Conissuer line to AN GMB. The water with the Conisseur line always looked odd and had crazy oil films or such on the surface. I conclude that line is just not good for soilless. Also iam not using any organics anymore. Before i was still using AN CalMag but that contains Kelp so i dropped it as well. Iam running fully sterile now.

Spray Interval:
Iam watering more on the dry side to promote fuzzy roots. Shorter pause resulted in less fuzzy roots.
2s on/7min off, delivering 3,2l daily for a 90l root chamber. Iam spraying with 15 bar, so relatively fine mist. At this point there is near zero runoff, so i might have to give a bit more water.

Light:
Around 800 PPFD LED. Relatively high light intensities early. Distance is around 40cm.

Temperature/Humidty:
This is a winter grow and every degree costs me money, so i run cool around 22 degree celsius.
I keep the leaf VPD at 1-1.1kPa.

Some hints:
- The most affected leaves are the ones close to the fan.
- Only bottom leaves are affected.
- The plant that is affected might have little bit less access to water since the container is tilted a bit.
- The plant that is affected had minor little brown spots from the very beginning. Maybe shes a bit sensitive.

My thoughts:
Iam growing relatively cold with high light intensity. It might be that i am dealing with LED/CalMag issues due to too little transpiration.

 

[Wastei]

You kinda answered your own question with low temps and humidity. It's hard to grow in hydro below 24C ambient. Calmag is not in any way needed growing in Aeroponics with a complete plant food.

You could probably double your feeding frequency and lower nutrient strength for better results. You should'nt need more than 1000µS in veg doing HPA Aero IMO and that being on the higher end.

You're using too much light for the stage of growth and for you environment(low temps and humidity). Excess light will cause symptoms of Potassium, Calcium and Magnesium deficiency. You won't get proper transpiration pushing high light intensity without optimal temps and humidity.

 

[cage]

Yes, definatly looks like mild calcium deficiency.
Not sure how those ferts come out as for K:Ca:Mg ratios.

But I've had something very similar with my plants before.
The plants were small with establishing roots and the lower leafs kept dropping looking just like yours.
While otherwise the plant looked great and roots were growing great.

Then I had Maxigro running which had too much K to Ca ratio.
Which probably was biggest contributor to my issue.

Transpiration is the other big weapon with calcium,
but looks like you should have decent enough air flow with your fan setup.

Temps could be higher, but enough airflow and low humidities would be plenty for transpiration.
Might hurt max yields with being low temp and transpiration dropping it further.
But shouldn't be an issue in veg.

So I'd suggest you look at what you are running for the K:Ca:Mg ratios.
Normal ratios would be around 6:3:1 or 6:3:1,5.
So if normal is like 100ppm K, 50ppm Ca, 25ppm Mg,
I'd suggest you try decreasing the K:Ca ratio a bit.

 

[Wastei]

Yes, definatly looks like mild calcium deficiency.
Not sure how those ferts come out as for K:Ca:Mg ratios.

But I've had something very similar with my plants before.
The plants were small with establishing roots and the lower leafs kept dropping looking just like yours.
While otherwise the plant looked great and roots were growing great.

Then I had Maxigro running which had too much K to Ca ratio.
Which probably was biggest contributor to my issue.

Transpiration is the other big weapon with calcium,
but looks like you should have decent enough air flow with your fan setup.

Temps could be higher, but enough airflow and low humidities would be plenty for transpiration.
Might hurt max yields with being low temp and transpiration dropping it further.
But shouldn't be an issue in veg.

So I'd suggest you look at what you are running for the K:Ca:Mg ratios.
Normal ratios would be around 6:3:1 or 6:3:1,5.
So if normal is like 100ppm K, 50ppm Ca, 25ppm Mg,
I'd suggest you try decreasing the K:Ca ratio a bit.

He's running a complete plant food with mineral ratios calculated and all in range. Like I mentioned in earlier post he should skip the Calmag since there's enough Ca/Mg already in the base mix for growing in Aero.

The problem is the environment. Cannabis is a hyperaccumulator and will grow well with many mineral ratios. It's not often anything wrong with the plant food, it's often down to grower error.

There's nothing wrong with either Maxigrow or Bloom and people use them from start to finish without showing any deficiencies.

 

[endorflight]

Thank you @Wastei, your a legend on this forum!
Thank you soo much @cage, you already helped me big time in the first grow!

I added the CalMag this grow when i saw the spots on the one plant when it was still tiny. Might be that back then i already had too much light.


Last grow my plants would not accept high light intensity later on, so this time i wanted to train them early.

Heating is expensive as i have a ceramic air heater right now. Outside its around zero degree celsius and iam pulling direct air. Lately i insulated the inflow tubes to deal with condensation.



Iam considering such thing

or infrared lights to cut down on the heating cost. Iam also thinking about getting a HPS for winter time.

Here is a full picture of my setup:



This is my second gen aeroponics system with excessive root oxygenation. I have 8 labyrinth air entries into the root chamber. A fan is constantly pulling the fog out of the root chamber back into the reservoir where it gets defogged by beeing shot onto the water surface. The drain of the root chamber exits under water, so fog cannot reenter back into the root chamber. That way i constantly draft fresh oxygen into the root zone. So the mist is not evaporating out of control in the root chamber anymore. Inside the root chamber there is super fine 15 bar mist followed by dry air. So far it is promising. The lesson i think i learned is in aero oxygen is still not guaranteed due to the high humidity by uncontrolled evaporation of the mist. Iam pulling much more oxygen in now than it would be possible with AAA.

The low temperatures in winter compliment my root zone which is now around 18 degree celsius. My focus last iteration was on root temps and oyxgen.

Searching for solutions, lets set the goal to push the plants to the maximum. Heat is expensive, dehumidicifation is affordable and i have lots of capacity, however plants did not response good so far.

 

[endorflight]

The plants were small with establishing roots and the lower leafs kept dropping looking just like yours.

I dont percive the lower leaves as dropping, they are adjusting to receive reflection light. I trained these plants but they have so short internode distance and such big stems its hard to do. I used some plastic "Bends" but they were far too small. These leaves also are huge, bigger as my hand. They look like super oxygenated alien planent leaves.

Overall i hesistate to cut too much leaves. This grow i cut the tap root, instantly some of the leaves died. So since then i beleive in kind of a equilibrium of the plant, aka it grows exactly as it should be. Cut too much roots, leaves die, cut too much leaves, roots die (which is unseen with soil).

 

[endorflight]

I'd suggest you try decreasing the K:Ca ratio a bit.

Do i understand that correctly as adding some more mono calcium? I ordered the Canna mono calcium.

 

[endorflight]

You won't get proper transpiration pushing high light intensity without optimal temps and humidity.

To be said i have a good VPD as i set it to, as my system runs VPD based. My own system humidifies/dehumidifies based on leaf VPD. The temperature is low but the humidity is definitly in check (At least as far as i set the VPD range with my knowledge). I have very accurate temp/humidity sensors and measure leaf temp with very accurate infrared measuring device.

 

[cage]

I dont percive the lower leaves as dropping, they are adjusting to receive reflection light. I trained these plants but they have so short internode distance and such big stems its hard to do. I used some plastic "Bends" but they were far too small. These leaves also are huge, bigger as my hand. They look like super oxygenated alien planent leaves.

Overall i hesistate to cut too much leaves. This grow i cut the tap root, instantly some of the leaves died. So since then i beleive in kind of a equilibrium of the plant, aka it grows exactly as it should be. Cut too much roots, leaves die, cut too much leaves, roots die (which is unseen with soil).

Yes, yours might be even milder deficiency than I had.
Mine grew out of it fine too,
bigger root system and some more calcium in relation to K probably did most of the lifting.

People go pretty heavy with their pruning especialy in veg, from complete defoliation to lollipopping.

As for the Mono-calcium, I wouldn't suggest such products, because they are pretty overpriced for the calcium you get.
So goal I'm suggesting is just increase the ratio of calcium in relation to K.
Personally I have some calcium nitrate and gypsum for when I need calcium.

"A nutrient antagonism is when an excessive concentration of one nutrient inhibits the uptake of another. Since K, Ca, and Mg have similar properties, and are taken up in a similar fashion, too much of one nutrient can inhibit the uptake of another nutrient. "
And while calcium uptake is semipassive, meaning that the transpiration is key in getting the calcium to the plant.
You can increase the ppm of calcium and get more of it with less water.

And I dont mean to really disagree with Wastei, since it's pretty accurate.
But if Maxigro or any other product has "all" the nutrients needed, doesn't mean it wouldn't be beneficial to tune it up,
especially for certain enviroment.

 

[cage]

To be said i have a good VPD as i set it to, as my system runs VPD based. My own system humidifies/dehumidifies based on leaf VPD. The temperature is low but the humidity is definitly in check (At least as far as i set the VPD range with my knowledge). I have very accurate temp/humidity sensors and measure leaf temp with very accurate infrared measuring device.

The other option would be to decrease the humidity a bit to increase transpiration.
You could even check the leaf temp difference if you decrease the humidity a little.

 

[endorflight]

bigger root system and some more calcium in relation to K probably did most of the lifting.

The root system this time is incredible big, at least double the size end of veg than end of last grow. ill try to make some pictures. As said i had browning with the higher >1000k EC, but since then the roots literally exploded, growing up the walls and what not. They formed a 5 cm thick mat on the ground, so big i might get problems to support it.

So, what i will do right now, based on you guys suggestions, is to increase the temp +1 degree celsius and increase the VPD +1 kPa. In this case i will set these in my vegetation grow profile which will have a linear transition to the flower grow profile. Adjusted automatically every day.

Also ill cut down on the CalMag by 50%. One thing i try to incorporate is not to make super big changes, but small ones at a time.



Seeing tools like Trollmaster, i can tell there is a whole other dimension of control that can be unlocked using software

 

[endorflight]

Iam off meds guys, so please bare with me if iam flipping a bit

Attached are the root pictures. I must be at least somehow in the ballpark.

As of now i think the problem should not be solved via temperature and/or humidity. One degree doesn't make such a big difference, i definitively cannot go high temp or ill get root zone problems. Temperature and humidity should be allowed to vary a bit without the plant getting such significant deficiency. It must be robust somehow.

Increasing the VPD, i feel like it increases the symptoms a little, like when everything is running faster also the problem manifests a bit more.
I feel more like, until this problem is solved, i cannot drive the VPD much higher!

I could reduce the light, however the goal is to max out everything until CO2 becomes the limiting factor. I hardly cant accept below 1000 PPFD.
The diagnose now is that Ca uptake is the limiting factor.

So goal I'm suggesting is just increase the ratio of calcium in relation to K.

I agree. For my understanding the best approach would be to solve it with the nutrients.

Options:
1) Add mono Ca. Reduce CalMag or remove it completely.
2) Reduce EC to 800 to reduce K to have better Ca update. However i dont see any signs of the EC beeing too high. Not a single burnt tip. No browning on the roots.
3) Change PH. Iam mostly running with 5.8 PH. Until i replace the solution it goes to 6.1. However it looks like Ca is best taken up at 6.2, or lower at 5.5.


KKfarming has this on their website which would pay into that:
"In Aeroponic growing its recommended to set pH levels a little lower than in hydroponic systems."
"We have had good experiences with a pH value in the range of 5.2 - 5.5! Moreover we recommend to let the level oscillate in this range.".

What do you think?

 

[cage]

With lower end of temperature range you might not be able utilize all of the 1000ppdf,
not quite sure of the temperature plateus.

The increased VPD either from extra temperature or lower humidity should always increase the transpiration and thus some Ca intake.
But getting much out of range there too comes with problems.
So like we established you might want to increase the Ca concentration.

your option 1, is fine except the pricey mono-canna

option 2, still havent had a close look what your fertz come out, but if similar mix like with GHE,
you could skip the grow portion of the mix which usually is potassium and nitrogen and some Mg in case of GHE.
This would reduce the K,Mg and thus increase the Ca ratio.

option 3, is very fine to try, I usually aim for the 6 nowadays anyway

Also I'd recommend to don't do too big changes because
the root trouble you had before could very well contribute to some nutrient deficiencies.

Roots looking good now!

 

[Wastei]

Iam off meds guys, so please bare with me if iam flipping a bit

Attached are the root pictures. I must be at least somehow in the ballpark.

As of now i think the problem should not be solved via temperature and/or humidity. One degree doesn't make such a big difference, i definitively cannot go high temp or ill get root zone problems. Temperature and humidity should be allowed to vary a bit without the plant getting such significant deficiency. It must be robust somehow.

Increasing the VPD, i feel like it increases the symptoms a little, like when everything is running faster also the problem manifests a bit more.
I feel more like, until this problem is solved, i cannot drive the VPD much higher!

I could reduce the light, however the goal is to max out everything until CO2 becomes the limiting factor. I hardly cant accept below 1000 PPFD.
The diagnose now is that Ca uptake is the limiting factor.


I agree. For my understanding the best approach would be to solve it with the nutrients.

Options:
1) Add mono Ca. Reduce CalMag or remove it completely.
2) Reduce EC to 800 to reduce K to have better Ca update. However i dont see any signs of the EC beeing too high. Not a single burnt tip. No browning on the roots.
3) Change PH. Iam mostly running with 5.8 PH. Until i replace the solution it goes to 6.1. However it looks like Ca is best taken up at 6.2, or lower at 5.5.
View attachment 5452075

KKfarming has this on their website which would pay into that:
"In Aeroponic growing its recommended to set pH levels a little lower than in hydroponic systems."
"We have had good experiences with a pH value in the range of 5.2 - 5.5! Moreover we recommend to let the level oscillate in this range.".

What do you think?

It's better to adjust pH according to plant response than general rules. You won't get more Calcium in the plant by changing the mineral ratios, you get more Calcium in the plant by better transpiration through changing the environment.

Aim for a pH of 5.8 in Aero and if you experience Ca/Mg issues raise that slightly, use as little light as possible in veg to save electrical cost. You should ultimately only use enough light intensity to stop undesired stretch.

The plant won't grow faster being pushed with a lot of light in veg, this has been confirmed for decades from growers experience on the forums. You can't force transpiration over the genetic potential, you can only raise it slightly with supplemental CO2 but that's about it.

The only time I use maximum light intensity is for 4-6 weeks in peak flower since I follow the plant transpiration rate and pushing excess light stop optimal transpiration. I can't run high intensity lights with desired lower humidity and temps in late flower as an example. You adjust the environment for the stage of growth and as a general rule less is more growing Cannabis!

 

[endorflight]

Thank you guys! Your input is soo much appreciated, cant express.

I guess i have to loose my horns and accept some limits. Nothing better than some straight words from experienced growers.

While iam processing the information, here is whats in my reservoir since 2 days. Flower has started 3 days ago.

Mixed in this order:
45L RO Water
10ml AN Rhino Skin (Silica)
20ml Canna CalMag
10ml AN Bud Ignitor
60ml AN pH Perfect Grow Micro Bloom - Micro
60ml AN pH Perfect Grow Micro Bloom - Grow
60ml AN pH Perfect Grow Micro Bloom - Bloom
40ml Purolyt (HOCL)

EC 1050
PH 5.9

 

[cage]

Thank you guys! Your input is soo much appreciated, cant express.

I guess i have to loose my horns and accept some limits. Nothing better than some straight words from experienced growers.

While iam processing the information, here is whats in my reservoir since 2 days. Flower has started 3 days ago.

Mixed in this order:
45L RO Water
10ml AN Rhino Skin (Silica)
20ml Canna CalMag
10ml AN Bud Ignitor
60ml AN pH Perfect Grow Micro Bloom - Micro
60ml AN pH Perfect Grow Micro Bloom - Grow
60ml AN pH Perfect Grow Micro Bloom - Bloom
40ml Purolyt (HOCL)

EC 1050
PH 5.9

Good luck, keep an eye how things develop.

Also checked out your Grow product, so it only contains 1% N, 4% K, 0,3% Mg, 0,5% Sulfur.
And the Canna CalMg, is 5% N, 5% Ca, 1,5% Mg.

So you are getting plenty of extra N with the CalMg.
And Grow has quite alot of potassium.

You could drop the Grow now, to reduce a bit of the K and start leaning of N.
And go 1ml micro per 1ml bloom
Then after 2weeks drop the CalMg, to reduce some Ca and N.
Adjust the strength to remain somewhat constant or to needs.
Then you can increase the bloom to micro portion after 4weeks like 2 bloom to 1 micro or 1,5 bloom to 1micro.
(with GHE this is called lucas formula when going 2to1 with bloom/micro)

Here's a few pics to get an idea at what points of growth certain elements are more required.

 

[OneHitDone]

Thank you guys! Your input is soo much appreciated, cant express.

I guess i have to loose my horns and accept some limits. Nothing better than some straight words from experienced growers.

While iam processing the information, here is whats in my reservoir since 2 days. Flower has started 3 days ago.

Mixed in this order:
45L RO Water
10ml AN Rhino Skin (Silica)
20ml Canna CalMag
10ml AN Bud Ignitor
60ml AN pH Perfect Grow Micro Bloom - Micro
60ml AN pH Perfect Grow Micro Bloom - Grow
60ml AN pH Perfect Grow Micro Bloom - Bloom
40ml Purolyt (HOCL)

EC 1050
PH 5.9

How strong is the Hypochlorous product you are using? Have you have good results with it in the past?