Why?

I'm growing Glueberry Auto's using an Autopot system with coco coir and Canna A/B at 52ml each, Bulletproof 3.5 ml, and CalMag 30ml, all numbers are total dose in 8 gallons of H2o. Using Kind K5 XL 1000 @+/_ 30 Inches from tops, RH btwn 35 and 60 (swings are tough to control) PH 6.26., PPM now 628 down from 770s (no overt signs of nute burn noted)

These girls are approximately 7 or 8 weeks old at this point and are showing wonderful flower production but despite my efforts to adjust ph up from 5.5 where it normally sat, to 6.2 to open it for calcium have only shown a continuation of these Brown spots which 1st started on the lowest leaves and are now showing towards the top of the plant...reservoir Temps are good btwn 62 and 70F and have a root mat to offset floor chill set at 65F. This is my second attempt at Auto's and is way better than the first run which was done remotely and failed miserably! I could use some direction and added some pics...T p.s. pic shot through safety glass lens! Thx for looking.

 

[St. Tom]

im thinking possible salt buildup as i get it a lot on my autopot girls I'm going to call @Mañ'O'Green in as he's our nutrition guy he may be able to work out whats going on

 

[Mañ'O'Green]

Well it looks like too much of something or a PH problem. I am working on getting lab equipment so I can figure out the plague we have in autos. I cannot prevent this in my own grows and I just do not know where we are going wrong. I know that the balance in our nutrients is the cause and often for new growers it is too much Cal-mag. I am very careful and still get it. The good thing is it does not stop us from getting a good crop.

I really thought I was hot on the trail and made some changes to my nutrient blend and damn I still got some?

Make sure your PH pen is calibrated and back off on the cal-mag. I will know more in the next few grows as I test the shit out of everything.

 

[Goud S!]

Well it looks like too much of something or a PH problem. I am working on getting lab equipment so I can figure out the plague we have in autos. I cannot prevent this in my own grows and I just do not know where we are going wrong. I know that the balance in our nutrients is the cause and often for new growers it is too much Cal-mag. I am very careful and still get it. The good thing is it does not stop us from getting a good crop.

I really thought I was hot on the trail and made some changes to my nutrient blend and damn I still got some?

Make sure your PH pen is calibrated and back off on the cal-mag. I will know more in the next few grows as I test the shit out of everything.

I've been pretty diligent about calibrating both my TDS meter and my ph pen. It is very confusing because one article says you can't add too much Calmag and another says be careful and then another says maybe it's a Phosphorus problem... I initially thought that keeping PH in the reservoir towards the 5.5 5.6 end was potentially making the calcium and magnesium unavailable so I have since raised it to the 6.2 range. I think one of my major issues is that I am trying to scale down the nutes based off a feed schedule for photo's. The other side of this is that the time frame is waaaay condensed so trying to match a 10 or 11 week grow off a 16 to 18 week schedule is confusing...where do they correlate and where do I titrate based on age????? I keep testing and try and this one is better than the last run so....I will back off the calmag....but keep the PK13/14?

 

[Mañ'O'Green]

Based on my research this is a good starting point for nutrient balance but there is too much latitude. I have stayed in these and still have symptomatic leaves. For sure outside of these ranges you will have trouble. This chart is in weight/l not EC.

Now about the Calcium thing. Most soil vendors put calcium in as part of the base (long lasting dolomite lime). Coco should be washed and precharged by you or the vendor. Then most nutrient lines have calcium in the base nutrients. In coco you should use nutrients designed for coco and it will have calcium in it at the rate for coco. Then if you use tap water to fertigate with it will have from a little to too much - 100PPMs+ of calcium.

Then we get a new grower with a bottle of Cal-Mag in his/her hand. So you see how easy it is to end up with too much.

That is not the only thing that can cause symptomatic leaves. RH/temp can cause it also - VPD out of range.

Not is not easy being a farmer. Every crop you get across the finish line is a winner.

 

[THE BEAR]

@Mañ'O'Green your a smart guy keep up your excellent work mate, I'd say you've saved thousands of autos, other ppls too,
Well done

 

[Olderfart]

Based on my research this is a good starting point for nutrient balance but there is too much latitude. I have stayed in these and still have symptomatic leaves. For sure outside of these ranges you will have trouble. This chart is in weight/l not EC.

View attachment 1312176

Now about the Calcium thing. Most soil vendors put calcium in as part of the base (long lasting dolomite lime). Coco should be washed and precharged by you or the vendor. Then most nutrient lines have calcium in the base nutrients. In coco you should use nutrients designed for coco and it will have calcium in it at the rate for coco. Then if you use tap water to fertigate with it will have from a little to too much - 100PPMs+ of calcium.

Then we get a new grower with a bottle of Cal-Mag in his/her hand. So you see how easy it is to end up with too much.

That is not the only thing that can cause symptomatic leaves. RH/temp can cause it also - VPD out of range.

Not is not easy being a farmer. Every crop you get across the finish line is a winner.

Point of clarification - some of the ppm levels in your table are listed as elemental (eg. only the S in SO4 counts), but others are not listed as elemental. What exactly is included in the PPM calculations for these other compounds?

Thanks for all your efforts with this MOG, you are helping a lot of people.

 

[Mañ'O'Green]

Point of clarification - some of the ppm levels in your table are listed as elemental (eg. only the S in SO4 counts), but others are not listed as elemental. What exactly is included in the PPM calculations for these other compounds?

Thanks for all your efforts with this MOG, you are helping a lot of people.

Those are ION that the plant can utilize. The chart is not in EC. It is in weight of ION per liter.

 

[Olderfart]

Those are ION that the plant can utilize. The chart is not in EC. It is in weight of ION per liter.

Sorry I was not clearer with my question - I understand what the ppm refers to, weight of the substance per volume of nute mix. What I am not sure of is why the term elemental is not used for all the nutrient ions in the list. If S is listed as elemental ppm to exclude the weight of the oxygen, why is Molybdate not listed the same way?

I'm not trying to pick nits, just trying to understand exactly how the calculations work. For my next grow, I may use a spreadsheet to calculate exactly what my nute mix is during the grow, and the data that you present here will help a lot - if I can make the appropriate calculations from my nute specs. Garbage in, garbage out as the saying goes.

 

[Mañ'O'Green]

Sorry I was not clearer with my question - I understand what the ppm refers to, weight of the substance per volume of nute mix. What I am not sure of is why the term elemental is not used for all the nutrient ions in the list. If S is listed as elemental ppm to exclude the weight of the oxygen, why is Molybdate not listed the same way?

I'm not trying to pick nits, just trying to understand exactly how the calculations work. For my next grow, I may use a spreadsheet to calculate exactly what my nute mix is during the grow, and the data that you present here will help a lot - if I can make the appropriate calculations from my nute specs. Garbage in, garbage out as the saying goes.

I believe that as opposed to just an ION the form absorbed by the plant is the element itself. I am not a chemist because I do not want to go down that rabbit hole. You have my permission to venture there.

I have worked on just such a spreadsheet. I have found several formulas to convert the guaranteed analysis to PPM in EC. They don't seem to verify with measured PPM. That said guaranteed analysis is a minimum so you already have slop in the equation. I worked the problem by taking the measured PPM and divide it by the percentages of the GA. I have taken 5 gallons of water and added 10g MC Part A Measured the PPM on the Hanna scale and did the same for Part B. I still have something wrong.

I am supposed to get some Lab Equipment but it is not moving as fast as I am.