From deficiency, to toxicity, I think :/ Pls Help.

The pic tells the perfect story... Too little at the rust spot bottom and too much at the dark green claw top?

Growing in coco. This is the first time I'm using GH Flora 3 part for soft water.
I use RO water at PH5.8 and the GH recommended ratio of Bloom:Micro:Grow @ 1:2:3 for growing @ 500ppm

The first leaves had rust spots. (see pic) It wasn't fungus or pests. After loads of googling I came to the conclusion that it was CalMag deficiency. I learned that RO water needs CalMag as the GH line for soft water has an insufficient amount for RO water.

I then picked up a bottle of CalMag. I added some to my RO water until I reached 150 PPM (around 3ml per gallon) and proceeded to add Bloom:Micro:Grow @ 1:2:3 for growing @ 500ppm total. PH 5.8.

The next set of leaves and several days later I get the dark green claws with a slightly "crinkled" leaf as well as a slight silver/metallic tint (see pic) google suggests its Nitrogen Toxicity. Is this because CalMag has nitrogen in it and I added too much? Its not wind burn as my fan is very gentle. Its possible the light was too bright for the first few days. I flushed last night until the runoff was less than 100PPM.

Kabul Auto. 650w LED at 60% power / 35k lux at the plant top. 20/4 schedule.



What should the added CalMag be before adding the Micro-Grow-Bloom... Or am I missing something entirely?

Thank you.

pH fluctuations. Either from wrong pH or most likely parts of the coco are getting too dry.

Nutty sKunK said:

pH fluctuations. Either from wrong pH or most likely parts of the coco are getting too dry.

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My nute water is always PH 5.8 and the coco is always consistently moist. I enjoy checking it at least twice a day. It's possible I may have skipped on checking PH for maybe a single watering but its unlikely. Any other thoughts? Thank you

What is your feeding schedule?
Do you always feed to substantial run off?
Do you ever use plain water?

MickFoster said:

What is your feeding schedule?
Do you always feed to substantial run off?
Do you ever use plain water?

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Once every second day. Reason is I'm using an airpot and the pot is a little lighter on the second day due to the fan blowing a breeze against the sides.
Yes, I always let the water run through thoroughly. I do this as I learned all about the salt build up.
No plain water ever. I buy RO water that has a PH 5.8. and Zero PPM. You cant drink or use the tap water where I live... its terrible.

I suggest you start feeding at least once a day to substantial run off.

Little-Leopard said:

I read this on the fastbuds site: "When using cal/mag and working with high amounts of phosphorus you risk locking out the phosphorus with too much calcium. Regardless of pH or any other factors too much calcium will lock out phosphorus very aggressively leading you to think there is ph lockout." I dont think this is the issue considering Im using t

Once every second day. Reason is I'm using an airpot and the pot is a little lighter on the second day due to the fan blowing a breeze against the sides.
Yes, I always let the water run through thoroughly. I do this as I learned all about the salt build up.
No plain water ever. I buy RO water that has a PH 5.8. and Zero PPM. You cant drink or use the tap water where I live... its terrible.

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Do you PH the nutrients solution before feeding the plants? If the RO water has a PH of 5.8 then you add nutrients they normally lower the PH

MickFoster said:

I suggest you start feeding at least once a day to substantial run off.

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I was going to suggest same. No matter how saturated you feel it is it’s best to water daily with coco.

Treesomewanted77 said:

Do you PH the nutrients solution before feeding the plants? If the RO water has a PH of 5.8 then you add nutrients they normally lower the PH

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It does sometimes drop to 5.7 and 5.6...never lower.

Treesomewanted77 said:

I was going to suggest same. No matter how saturated you feel it is it’s best to water daily with coco.

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Ill start tonight and see how it progresses.

Little-Leopard said:

My nute water is always PH 5.8 and the coco is always consistently moist. I enjoy checking it at least twice a day. It's possible I may have skipped on checking PH for maybe a single watering but its unlikely. Any other thoughts? Thank you

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Well it’s pH related regardless of the reason. The tail tale sign is brown in the margins (usually young plants) and no yellow before the brown meets the green part of the leaf. If there is yellowing coupled with brown spots that’s calcium def.

hopefully watering every day will keep the pH stable

Nutty sKunK said:

Well it’s pH related regardless of the reason. The tail tale sign is brown in the margins (usually young plants) and no yellow before the brown meets the green part of the leaf. If there is yellowing coupled with brown spots that’s calcium def.

hopefully watering every day will keep the pH stable

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As a new grower, I have no idea how I would have figured that out if it were not for your answer...google only tells you so much. May I have your PH recommendations?
Thank you... Ill pay closer attention to PH, and water daily. Will post an update.

There's no such thing as calcium deficiency with Cannabis. Cannabis will huff calcium fumes from miles away before it goes Ca deficient. Literally never seen calcium deficiency in Cannabis ever , no one has, ever. Everyone thinks cannabis is a nutrient hog because they lock everything out with calcium, and call everything a calcium deficiency..


You had boron and manganese deficiency, caused by excess calcium, and you made it worse by adding more calcium. Next you'll have potassium deficiency from adding those micronutrients. This is what growing "forum style" gets you. Chasing your tail growing larfy mids.

Clawing, dark leaves, etc is CALCIUM TOX/BOR-POT DEF, not Nitrogen related. The stupid Marijuana leaf deficiency charts are utter bullshit, designed to sell more calmag and fuck your shit up, so you buy more shit, and more shit, and more shit..


This calcium toxicity is so common in Cannabis, someone would have to design a fertilizer with every mineral except Calcium to correct the epidemic of crusty blue island boy looking buds with urinal cake terps.

Little-Leopard said:

As a new grower, I have no idea how I would have figured that out if it were not for your answer...google only tells you so much. May I have your PH recommendations?
Thank you... Ill pay closer attention to PH, and water daily. Will post an update.

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I don’t have much experience with coco but you feed around 5.8-6.2. @MickFoster knows his shit so hopefully can chime in.

Also once your nutes is made up and adjusted for pH let it sit for 10 mins and check again. Just in case. If no difference no need to do it again.

But the pH fluctuations happen when the coco dries out (not completely just drier than what it was) and the pH will drift as a result. Same situation in soil. There is also an EC spike when the media dries.

Good luck!

Nutty sKunK said:

I don’t have much experience with coco but you feed around 5.8-6.2. @MickFoster knows his shit so hopefully can chime in.

Also once your nutes is made up and adjusted for pH let it sit for 10 mins and check again. Just in case. If no difference no need to do it again.

But the pH fluctuations happen when the coco dries out (not completely just drier than what it was) and the pH will drift as a result. Same situation in soil. There is also an EC spike when the media dries.

Good luck!

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I did some serious flushing. Flush, check PH, check PPM... redo, redo, redo. The PH was 5.6. I slacked off with checking PH after adding the nutes. The claws and color have already started showing signs of improvement. Thank you for your help.

Little-Leopard said:

I did some serious flushing. Flush, check PH, check PPM... redo, redo, redo. The PH was 5.6. I slacked off with checking PH after adding the nutes. The claws and color have already started showing signs of improvement. Thank you for your help.

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Aye from what I know coco is sensitive to pH. No worries and good luck!

Is there a reason you're using RO and then adding back the Ca and Mg you removed?

“ I slacked off with checking PH after adding the nutes…… “


Ph drift - move up to 5.9 after nute mix . You can run tap to solve cal mag issue as most city water has it .

xtsho said:

Is there a reason you're using RO and then adding back the Ca and Mg you removed?

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Well when I say RO water I really mean RO bottled water for human consumption. One cannot use the tap water here, its terrible. We have to buy water to drink... you will get the runs and possibly sick if you drink what's in the taps here. I use the bottled water for my plants. The nice thing is its very cheap and the PH is always 5.8

Budzbuddha said:

“ I slacked off with checking PH after adding the nutes…… “
Ph drift - move up to 5.9 after nute mix . You can run tap to solve cal mag issue as most city water has it .

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Great tip. This actually occurred to me while doing the flush... I kept correcting the PH back up to 5.8 after flushing when could have up'd the PH to 6 and then flushed less to 5.8 so to speak. I assume that's what you mean when you say 5.9... to account for the slight drop from nutes? As for tap water you can see my response above. Thank you