Magnesium and Potassium Lockout due to too much Calcium?

I've still problems with my plant and it's not over yet. I've read that too much calcium can lead to other nutrients beeing locked out. Since I have problems with my plant for a long time I start to think that this might be the case. I'm adding more and more Cal/Mag over time since it was looking like a Magnesium deficiency but it still progresses further. Once someone said maybe it's too much Cal/Mag so maybe he was right and others who said to raise the magnesium not.

My nutrient solution:

PH range: 5.8-6.3 most of the time(but sometimes it's 5.5-6.5 which is still ok I guess)
EC: 1280 uS/cm (0 EC distilled Water with 580 EC Cal/Mag and 700EC base nutrients)

Over time I've added more and more Cal/Mag since the deficiencies still carried on. But by now I start to think that it's not a magnesium deficiency due to not enough magnesium in the nute solution but a deficiency due to TOO MUCH calicium which starts to lock out the magnesium (and potassium eventually).

What do you think? It sounds a little bit overkill that 45% of my nute solution is Cal/Mag compared to 55% base nutrients (which also contain calcium and magnesium).

Does it sound off to you too that the nute solution consists of 45% Cal/Mag and still shows signs of magnesium deficiency (and eventually potassium deficiency)?

I've increased the Cal/Mag dosage 2 days ago since it still shows signs of Magnesium deficiency which made me think that I still need more BUT now 2 days after increasing the deficiency still spread (look at the comparison picture below). Do I have to give them more time to react to the higher Cal/Mag solution or do you think it's overkill and it might be a lockout problem due to too much Calcium by now? Or is two days not enough time to make a conclusion even if it's still progressing?

Plant comparison 2 days difference (left 2 days ago and right is today)
Look at the two big leaves on top. It grew but it's also more yellow after 2 days


EDIT: Hydro DWC with just water in reservoir.

I'd try feeding just the base nutrients with some additional Epsom salts. Combining Ca and Mg was one of the worst things that this industry has done. Try feeding at 1 to 1.2 EC with something like one gram Epsom salts per gallon of nutrient solution (you might need less, I usually use 2 grams epsom per 3 gallons of solution). Not sure if you are in Coco or soil, but be sure you are feeding this solution to plenty of runoff. Your issue could be EC buildup in the media as much as it could be from the Calmag. Feed to 20% runoff each time and see if it helps (without the Calmag). Maxigrow/bloom is an easy formula to use and get good results with.

Rurumo said:

I'd try feeding just the base nutrients with some additional Epsom salts. Combining Ca and Mg was one of the worst things that this industry has done. Try feeding at 1 to 1.2 EC with something like one gram Epsom salts per gallon of nutrient solution (you might need less, I usually use 2 grams epsom per 3 gallons of solution). Not sure if you are in Coco or soil, but be sure you are feeding this solution to plenty of runoff. Your issue could be EC buildup in the media as much as it could be from the Calmag. Feed to 20% runoff each time and see if it helps (without the Calmag). Maxigrow/bloom is an easy formula to use and get good results with.

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I grow with DWC. Only water in the reservoir. Ok you think 1 to 1.2 EC is not too much for a smaller plant? I was thinking about just using the base nutrients too so I will change the res soon and add only the base nutrients and will see how that goes! Thank you!

Edit: And since there is no media where EC buildup can occur since the roots are in just water it's more likely that it's too much Cal/Mag right?

RookieMuffin said:

I grow with DWC. Only water in the reservoir. Ok you think 1 to 1.2 EC is not too much for a smaller plant? I was thinking about just using the base nutrients too so I will change the res soon and add only the base nutrients and will see how that goes! Thank you!

Edit: And since there is no media where EC buildup can occur since the roots are in just water it's more likely that it's too much Cal/Mag right?

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How many ml's of calmag per gallon are you using?

ec121 said:

How many ml's of calmag per gallon are you using?

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I use this product Canna CalMag Agent (https://www.cannagardening.com/calmag-agent)

I use 1ml per litre so converting it would be about 3.8ml per gallon (US Gallons). Instructions on the bottle say to use 0.1-0.5 ml per litre to reach EC 0.45 but I need 0.8ml to reach a EC of 0.45 with distilled water. And since my deficiencies spread further even with EC 0.45 I used even more so now I was using 1.0ml per liter and reached EC 0.57... And STILL the deficiencies spread after 2 days (maybe I'm judging to fast). So I really think it's way too much Cal/Mag! 45% of whole nutrient solution was Cal/Mag. Doesn't sound right.

EC meter is calibrated.

Changed the reservoir yesterday. Just base nutrients and no Cal/Mag.

EC 1.08
PH 5.8

Will keep an eye on the plants if symptoms get better or worse!

Have you had repeated luck with distilled water? I know a lot of people who won't use it for the additional problems it can cause (not only because it's a bear to test but I believe it also is stripped of any dissolved oxygen). You might try with R/O water instead and see if that's part of your worries. I don't think you should need that much Ca/Mg...I generally add about .25EC to my filtered water.

I've just done the same thing to my plants. I think Ive been over calmagging them. I just cut out all calmag but kept feeding bloom nuts and they look better

LeastExpectedGrower said:

Have you had repeated luck with distilled water? I know a lot of people who won't use it for the additional problems it can cause (not only because it's a bear to test but I believe it also is stripped of any dissolved oxygen). You might try with R/O water instead and see if that's part of your worries. I don't think you should need that much Ca/Mg...I generally add about .25EC to my filtered water.

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I had zero problems with distilled water yet. I also aerate it so dissolved oxygen shouldn't be a problem.

For some people it's hard to test when it's still pure but as soon as the nutrients are added there shouldn't be a problem. At least I don't have a problem testing it. Maybe different meters are better than others when testing distilled. Some people are also testing with the drop solution test or some test paper you emerge in the water which is probably also not working with distilled water.

Anyway one day I probably will use R/O water since it's cheaper to produce!

I think so too that .57 EC was too high. I think I might have to add some too my base nutrients BUT not that much. maybe 0.1 or 0.2 EC that's all. But for now I keep testing with only base nutrients.

whelk said:

I've just done the same thing to my plants. I think Ive been over calmagging them. I just cut out all calmag but kept feeding bloom nuts and they look better

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My nutrient change is not that long ago so I still have to keep an eye on them BUT I think they are a little bit better too. I'll maybe need a little extra calmag but not that much as I've used before! I think my plant got overcalmagged from the beginning on... Over a month now. They are in terrible shape lol. We'll see how the new growth will look like in some days.

I'm not a hydro grower, but I like this chart. I think of it like "for when you're giving it more of "x" but the problem keeps getting worse." Look at how many other nutrients calcium can lock out when it's used in excess...

weedstoner420 said:

I'm not a hydro grower, but I like this chart. I think of it like "for when you're giving it more of "x" but the problem keeps getting worse." Look at how many other nutrients calcium can lock out when it's used in excess...

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Damn thank you! Looks like calcium is able to lock out a lot of nutrients! Saved it! And I think I used a LOT before!

I think I'm on the right track now only feeding base nutrients. The leaves don't feel as dry as before now. Maybe I will add just a little bit Cal/Mag later if she show signs but not as much as before!

RookieMuffin said:

I use this product Canna CalMag Agent (https://www.cannagardening.com/calmag-agent)
I use 1ml per litre

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The recommendation is 0.1 - 1ml/L that's a pretty wide range and you're at the max.
Jus sayin...

sh0wtime said:

The recommendation is 0.1 - 1ml/L that's a pretty wide range and you're at the max.
Jus sayin...

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On my bottle it says to use 0.1 - 0.5ml/L until EC 0.45 is reached. And I need 0.8ml to reach 0.45 EC... And when I still got deficiencies I started using 1ml and 0.58EC. So yeah I was using too much... maybe 0.2ml would have been enough with enough base nutrients.

Some days are over now I think it's still progressing a little but I will wait some more days before adding cal/mag.

What would you add? Only magnesium (epsom salt) or the cal/mag I already have?

How to add only calcium to the reservoir? Epsom salt is for magnesium. What is for calcium?

From the deficiency chart it really does look like a magnesium deficiency.
But with you feeding so much cal/mag, how can it be?




What Does Excessive Calcium Do?

Too much calcium in your weed plants can lead to some severe consequences. The most obvious problem that you’ll see if you overdo it with a calcium additive is leaf burn. The cannabis plant is reacting to the excessive levels of calcium and is trying to push it out from the leaf tips. This causes necrosis (death) of the leaf tips, and they will be a yellow/brown color.

Besides causing leaf burn, excess calcium doesn’t actually create such drastic symptoms as a deficiency. Instead, too much calcium in your cannabis plants will actually lead to problems in other nutrients, such as magnesium and potassium. This situation presents a very frustrating problem when growing cannabis. Too much calcium will lock out magnesium or potassium, and the only way to correct the problem is by first dealing with the calcium issue.

So, although you’re experiencing potassium and magnesium related symptoms, the actual root of the problem stems from too much calcium. Dealing with an excess calcium problem doubles or triples your work by making it necessary for you to also try and fix your magnesium and potassium issues. It can also lead you astray chasing other nutrients, while the calcium problem remains active..




I'm not sure tbh, mbe a pro can weigh in here.

sh0wtime said:

From the deficiency chart it really does look like a magnesium deficiency.
But with you feeding so much cal/mag, how can it be?

View attachment 5251099


What Does Excessive Calcium Do?

Too much calcium in your weed plants can lead to some severe consequences. The most obvious problem that you’ll see if you overdo it with a calcium additive is leaf burn. The cannabis plant is reacting to the excessive levels of calcium and is trying to push it out from the leaf tips. This causes necrosis (death) of the leaf tips, and they will be a yellow/brown color.

Besides causing leaf burn, excess calcium doesn’t actually create such drastic symptoms as a deficiency. Instead, too much calcium in your cannabis plants will actually lead to problems in other nutrients, such as magnesium and potassium. This situation presents a very frustrating problem when growing cannabis. Too much calcium will lock out magnesium or potassium, and the only way to correct the problem is by first dealing with the calcium issue.

So, although you’re experiencing potassium and magnesium related symptoms, the actual root of the problem stems from too much calcium. Dealing with an excess calcium problem doubles or triples your work by making it necessary for you to also try and fix your magnesium and potassium issues. It can also lead you astray chasing other nutrients, while the calcium problem remains active..

I'm not sure tbh, mbe a pro can weigh in here.

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I think it is an excess of calcium too! Because I was feeding a lot of magnesium and still got problems! And checking deficiencies it looks like Magnesium deficiency and also looks like Potassium deficiency (dieing leaf tips and edges).

I can tell you this: I grow in soil, but I also became too much of a fan of that cal/mag stuff.
Kept my plants very green and overall healthy and I also went towards feeding less base nutes and more of the cal/mag agent.
But mine also have leaf tips burning a bit now, and some yellowing happening even tho they had plenty of NPK.
I never used more than 0.5ml / L, but 50-75% base nutes.

I will definitely either do a nutes-wateronly-nutes feeding or drop the dosage by 50% next grow. It was actually the first time I used almost only canna components, I'm not quiet settled in.

Seems like it took quiet a while for them to get affected by it but once you hit the mark, it rapidly transforms your plants.
Even more reason for YOU to be careful, since you're growing in hydro, my friend.

You still have plenty of time to recover, so imma wish you the best of luck.

RookieMuffin said:

I think it is an excess of calcium too! Because I was feeding a lot of magnesium and still got problems! And checking deficiencies it looks like Magnesium deficiency and also looks like Potassium deficiency (dieing leaf tips and edges).

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I think you are on the right track following @Rurumo 's advice. Calmag is not a cureall, and most of the time not the solution

sh0wtime said:

I can tell you this: I grow in soil, but I also became too much of a fan of that cal/mag stuff.
Kept my plants very green and overall healthy and I also went towards feeding less base nutes and more of the cal/mag agent.
But mine also have leaf tips burning a bit now, and some yellowing happening even tho they had plenty of NPK.
I never used more than 0.5ml / L, but 50-75% base nutes.

I will definitely either do a nutes-wateronly-nutes feeding or drop the dosage by 50% next grow. It was actually the first time I used almost only canna components, I'm not quiet settled in.

Seems like it took quiet a while for them to get affected by it but once you hit the mark, it rapidly transforms your plants.
Even more reason for YOU to be careful, since you're growing in hydro, my friend.

You still have plenty of time to recover, so imma wish you the best of luck.

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Mine went bad pret1ty fast and I was adding more and more Cal/Mag... One plant is as small as a 2 week old plant or something like that! But still alive that's a good thing lol

Thanks for wishing me luck. I hope it goes well! Right now it looks ok!

Boatguy said:

I think you are on the right track following @Rurumo 's advice. Calmag is not a cureall, and most of the time not the solution

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Thanks! I'm following @Rurumo 's advice right now. Still have to get some epsom salt but was feeding the base nutrients first to see how that goes. Don't want to feed too much again. As far as I can tell they even grow better and faster now!

But I think I might need some of the epsom salt because it's still progressing a little!

Hi I'm back!

I was following @Rurumo 's advice and the plants grew a good amount in the last 1.5-2 weeks. It took some time to get my hand on some epsom salt and I was adding it slowly day by day because I was scared of overdoing it again. I think the deficiencies are progressing slow now (or even stopped I will see how the new leaves look like in a week or so).

But I'm a bit confused. The magnesium deficiency might be good now (I will see) but I also think there are other deficiencies going on... Like I even get signs on the newest leaves and it somewhat looks like nitrogen or potassium deficiency not only magnesium (but I might be wrong I don't know!). Newest leaves get yellowing tips (N def?) which progresses further and the brown dieing edges on the leaves (K def?)...

That makes me think I'm maybe feeding not enough base nutrients. When I upgraded the base nutrients EC to 1.0 like rurumo said they started growing good (still deficient though because I didn't have epsom salt on hand) and now I think they stalled again maybe because EC with 1.0 was not enough for a plant this size after growing again. So some days ago I again raised base EC to 1.3 but I think they don't grow as fast as they could (I'm a noob idk maybe I'm wrong). And as I said it also looks like N or K deficiency.

So my question now is how much would you feed a plant this size in EC in DWC?

Biggest plant is about height 17.7 inch (45 centimeter) and width about 15.7 inch (40 centimeter). What would you feed?

And the smallest is the one that never grew well after it got too deficient it's maybe about 6 inch (15 centimeter) and looks like a clone lol. Not even branched out yet... just the stem and some leaves...

Here is a picture (I know it still looks deficient as fuck but maybe it's ok now due to epsom salt or maybe it's because of N or K)


And here is a picture from the top (notice the yellowing NEW leaves maybe N def? and the brown leaf edges/tips K def?)

Bro, you're definitely chasing your tail here. New leaves do not exhibit nitrogen deficiency before old leaves. It's harder when it's progressed to this point, but it just looks like a magnesium deficiency. A potassium deficiency would have the leaf margin turn necrotic first. Here you have interveinal chlorosis combined with necrosis on the leaflet margin. Advanced magnesium deficiency would turn the leaves necrotic but interveinal chlorosis would be exhibited before that happens and starting at the lower portion of the plant first.

What exactly are you feeding in ml's per gallon and your step-by-step process of adding nutes? EC is great when your EC meter is calibrated. When shits going south, you need to check everything. How much magnesium sulfate are you giving it? What is your light, it's distance, the dim setting, etc? Was the very first signs of interveinal chlorosis at the lower growth?