Calcium issue and questions

[greenjeans]

Firstly, let me post a couple of pictures of what I believe is a calcium issue.. Can someone confirm that my diagnosis is correct?



This is a 45 day old NLA in DWC.

Measures I have taken to correct:
PH had drifted to 6.2, I corrected to 5.7.
I added extra calmag into the res. I have been giving calmag at a low level because I am using tap water.


Here is my question:

I am finding conflicting information about nutrient availability. Different charts have different numbers regarding availability, mostly showing 5.8 to be a solid number that hits both cal and mag, but the Growweedeasy site says that calcium is best absorbed above 6.2.

What is the truth of this? Is calcium locking out in hydro above 5.8-5.9 like some of the charts say, or does it absorb better at a higher ph? This is the second time I have run into this problem, so I would like a definitive answer on calcium uptake as it relates to ph.

Thanks in advance for your help.

 

[Grim Reefer]

Hello GreenJeans,
Thats a cal diff alright for sure.
Now it is true that Cal is best absorbed at PH 6.2 but that doesnt suit your circumstances because your growing hydro.
Im sure there is a chart somewhere here on the forum just let me find it.
EDIT:
Here you go if you havent seen this already

pH and Nutrients Uptake Charts

This is probably over board but the right information is here. I grow in DWC at ph5.8 (the best PH for any hydro) the whole way through and have no problems so its sound to me like you just need to raise you cal& mg up a little. Autos are very heavy on cal/mg compared to photos, especially under LED.
​

 

[greenjeans]

Hello,
Thats a cal diff alright for sure.
Now it is true that Cal is best absorbed at PH 6.2 but that doesnt suit your circumstances because your growing hydro.
Im sure there is a chart somewhere here on the forum just let me find it.
EDIT:
Here you go if you havent seen this already

pH and Nutrients Uptake Charts

​

I have definitely been seeing all three of these charts. But they don't match up. If you notice, charts one and three show that 5.8 is optimum, whereas Chart 2 seems to suggest a ph more around 6.3-6.5 to be the number. And this article says that "Calcium deficiencies are more likely to appear when-Growing cannabis in hydroponics with nutrients that don't supplement calcium or when growing in water that has less than 6.2 pH"

http://www.growweedeasy.com/calcium-deficiency-cannabis

So that is 50/50, Two charts say 5.8 and one chart and an article on a pretty well-trusted site say around 6.3. The question is, "Which assesment is correct?".

 

[Grim Reefer]

I do apologies GreenJeens that PH Chart in the middle is old and really doesnt make any sense. Id be looking at the top and bottom one and both state 5.8 being optimum for Hydro where as PH 6.3-6.5 is for a soil or soiless growing medium.
Any of the Pro Growers on the AFN like Gangjomoto or Seymour buds all keep there PH at 5.8 and never go over 6.
Maybe this is something you should try out and see for yourself but as i said before i wouldn't recommend it.

 

[MedGrower]

Greenjeans, you're not the only one who has been asking why all those pH charts doesn't match up.

I am pH -heretic. When I grow with DWC and go below 6.0 pH in vegetative state I tend to get problems. So I grow in 6.2 pH just fine (grown very nice crops with pH 6.2 to 6.4 too!) and turn to 5.8 pH in later stage after couple weeks of flowering. I do not know why but seems like no matter how much calmag I add, I will have pH lockup of that stuff below 6.0 pH.

This just as a reference for you in case if your calsium -problem gets worse below 6.0 pH. This time around I did actually swing the pH between 6.2 to 5.7 each day to get the good stuff from the both ranges and seemed that my babies liked it a lot and perked up.

I bet everyones circumstances are different and the optimal ranges differs some so it would be difficult to know for sure what works the best without experimentation. I would bet that also the temperature of the water affects the pH absorbtion range as well as quality of the water. Chelators, such as fulvic and humic acid might widen the effective absorbtion range also.


There is also a very informative thread about pH here started by The Groff:
https://www.autoflower.org/f61/am-i-insane-lot-people-using-wrong-ph-29430.html


Another really good pH chart for DWC:

 

[Waira]

:tiphat: greenjeans- No doubt, Ca defc.,...(cheers GR, thanks for helping!)... and I hear you about the clusterfuck of charts, graphs, etc. that can confuse more than help- :slaps: LOL! .... personally I like the attenuating bar graphs best, as I think they represent the relative availability of a given nutrient vs. pH,.... I can only assume these are made with some sort of standard temp. and water chemistry as a baseline, as indeed these parameters have a big impact on both pH and availability-- (Med'- :thumbs,... So, use'm as a general guideline! Now, I'm not hydro savvy myself, but have lots of water chemistry background... as you see in the bar graphs, Ca availability is better outside the "optimal" pH, as are several others,... something that always mystified me, I must admit! Small wonder there's an apparent increased demand for Ca, and/or Mg, given their poor relative availability in this window-- ditto for others as well! Stray even a little, and something bad, or maybe good(?- LOL!) happens...:Woozy..?: ...Recommended ranges are trying to strike a best average across the board, it seems,... and then you have skilled folks getting great results at slightly different ranges that they find work best for their systems,... mix in the usual autoflower variability on nutrient needs and tolerances, and shit gets fuzzy fast! Here's the bar graph I prefer, from Rosenthal's book-->

>>> Too bad you're into bloom now, (I assume--?) -still might be okay, but we need to see where the buds are at in development... a nice couple rounds of foliar spraying along with soil dosing, would fix her right up and fast! It's the quickest, most direct route into the plant, and is particularly effective when dealing with nutrients that are poorly mobile within the plant-- Ca is one of them,...... very handy also, when needing to bypass trouble at the root level of things,... What's the ppm or EC of your tap water, BTW? I get what you thinking with this for Ca and Mg,... very little Mg ions in there, it's largely Ca,... those buffering carbonates are certainly nice to have though!

 

[greenjeans]

:tiphat: greenjeans- No doubt, Ca defc.,...(cheers GR, thanks for helping!)... and I hear you about the clusterfuck of charts, graphs, etc. that can confuse more than help- :slaps: LOL! .... personally I like the attenuating bar graphs best, as I think they represent the relative availability of a given nutrient vs. pH,.... I can only assume these are made with some sort of standard temp. and water chemistry as a baseline, as indeed these parameters have a big impact on both pH and availability-- (Med'- :thumbs,... So, use'm as a general guideline! Now, I'm not hydro savvy myself, but have lots of water chemistry background... as you see in the bar graphs, Ca availability is better outside the "optimal" pH, as are several others,... something that always mystified me, I must admit! Small wonder there's an apparent increased demand for Ca, and/or Mg, given their poor relative availability in this window-- ditto for others as well! Stray even a little, and something bad, or maybe good(?- LOL!) happens...:Woozy..?: ...Recommended ranges are trying to strike a best average across the board, it seems,... and then you have skilled folks getting great results at slightly different ranges that they find work best for their systems,... mix in the usual autoflower variability on nutrient needs and tolerances, and shit gets fuzzy fast! Here's the bar graph I prefer, from Rosenthal's book-->View attachment 441031

>>> Too bad you're into bloom now, (I assume--?) -still might be okay, but we need to see where the buds are at in development... a nice couple rounds of foliar spraying along with soil dosing, would fix her right up and fast! It's the quickest, most direct route into the plant, and is particularly effective when dealing with nutrients that are poorly mobile within the plant-- Ca is one of them,...... very handy also, when needing to bypass trouble at the root level of things,... What's the ppm or EC of your tap water, BTW? I get what you thinking with this for Ca and Mg,... very little Mg ions in there, it's largely Ca,... those buffering carbonates are certainly nice to have though!

Thanks for offering up yet another chart, Waira.

So according to that chart, despite the fact that it has a line at the 5.7-6.2 range, the optimum ph seems to be a 5.3. lol

I am quickly learning that for every question there are several different "camps" who have their own set of opinions, and unfortunately, the facts seem to often get completely lost among them. Not much different than any other subject on the web, I suppose.

In the end, the problem stopped progressing after I fiddled with the PH, and I thought it would, so this is really more about getting to the truth about which charts, and which proverbial camps are actually right. Or at least finding out which camp *I* belong to. lol

It seems that in this grow, the plants have preferred a higher ph in veg, and are now wanting something lower. This seems to line up with the information in the thread that Medgrower linked in his comment. And the theory really does seem to make good sense.

I guess that the answer for me is probably just to hit them harder with the Cal-Mag, veg around 5.9-6.2 and end up more around the 5.6-5.8 range later in the grow. At least with this strain.

 

[greenjeans]

I do apologies GreenJeens that PH Chart in the middle is old and really doesnt make any sense. Id be looking at the top and bottom one and both state 5.8 being optimum for Hydro where as PH 6.3-6.5 is for a soil or soiless growing medium.
Any of the Pro Growers on the AFN like Gangjomoto or Seymour buds all keep there PH at 5.8 and never go over 6.
Maybe this is something you should try out and see for yourself but as i said before i wouldn't recommend it.

Certainly no need to apologize. It seems that there are just a lot of different charts that disagree with each other. The fact that you dismiss the one that doesn't agree with your personal stance on the subject is, I'm sure, a reflection of what everyone is doing. Winging it, and then selecting the chart that goes along with what has worked for them. Although this approach reeks of confirmation bias, there is definitely a certain logic to it.

In the end, I wouldn't be surprised if the charts were created in much the same way, noticing problems at different ph levels and then charting based on notes taken throughout the course of several grows. I just wish there was more consensus and less speculation. And definitely less conflicting information.


Thanks to everyone for the info.

 

[lorcanlive]

Hi I started off growing an Auto but after it didn't flower at 65 days I put on 12x12, that was last week. Question is how much cal/mag should I feed cos I think Photos don't use as much as Autos? Anyone know?

 

[Chester]

Hi I started off growing an Auto but after it didn't flower at 65 days I put on 12x12, that was last week. Question is how much cal/mag should I feed cos I think Photos don't use as much as Autos? Anyone know?

I'd try 5 ml CalMag / gal every time or every other time you water ... adjust as needed ...