Am I looking at CalMag Nutrient deficiency here?

greentomatoes2025 · May 5, 2025

Hi all,

I'm days away from flipping to flower on this WW x BB photoperiod in coco. First time indoor grower. Have recently flushed 6 days ago with RO water as I believe I had N-Tox. Have fertigated every 2-3 days since as usual. Current run off is 1.4 EC and PH is 6.0.

Am I looking at Cal/Mag deficiency here?

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Cheers,

JIMKSI64 · May 5, 2025

I do not do coco but I hear stuff. Folks will want to know nute line and EC in and EC out. I assume you always use ro water but clarify if not. Also if it's an RO filter you should still check ppm cause they do have filter maintenance and can have a defect that is not working and can make EC read off so nute EC is off.
Coco guys around here are awesome.

greentomatoes2025 · May 5, 2025

JIMKSI64 said:
I do not do coco but I hear stuff. Folks will want to know nute line and EC in and EC out. I assume you always use ro water but clarify if not. Also if it's an RO filter you should still check ppm cause they do have filter maintenance and can have a defect that is not working and can make EC read off so nute EC is off.
Coco guys around here are awesome.

Thanks bro - First post so appreciated the feedback.

My nute line is as follows and all except the GT Coco A&B is not specifically known as they order bulk and repackage:
GT Coco A + B 2ml each/L
Silica 3ml/L
Nitrozyme 1ml/L
Rhizo 2ml/L
Super Juice 1ml/L
Fulvic 1ml/L
I'm using tap water to dilute with

Fertigating 1.5L every 2-3 days for 20% RO

EC in is 1.7
Tap water EC is 0.4
PH in is 6.0
I'm not using any filters for water.

Onelife · May 5, 2025

My guess is magnesium. Folier spray with Epson salt. Damage spots on leaves will not get better but should stop the problem.
But ask for a 2nd opinion

Illbill · May 5, 2025

I just grew some ww/bb in coco. It was a cal-mag whore. Do you have perlite in your coco mix?

LoveGrowingIt · May 5, 2025

The spots are indications of calcium deficiency. Magnesium deficiency is indicated by yellowing between the veins. There may be some of that, but it's slight. Use of a calmag product should help.

ArtfulCodger · May 5, 2025

The first thing I'd do is turn my light down a bit, until the symptoms stop increasing. It does look like you're outrunning Ca and (to a lesser extent) Mg. I'm not familiar with the nutes and supplements you're using, but it's probably worth doing some math to see how many ppms of Ca and Mg they've been getting, and adjust as needed. I'd wait on flipping until you get this sorted. Going into the stretch without enough Mg on board is a yield killer.

LoveGrowingIt · May 5, 2025

ArtfulCodger said:
The first thing I'd do is turn my light down a bit

I considered that, too, but didn't mention it because I haven't had my morning coffee yet.

ArtfulCodger said:
Going into the stretch without enough Mg on board is a yield killer.

This is great advice.

greentomatoes2025 · May 5, 2025

Onelife said:
My guess is magnesium. Folier spray with Epson salt. Damage spots on leaves will not get better but should stop the problem.
But ask for a 2nd opinion

Thanks for your input much appreciated!

greentomatoes2025 · May 5, 2025

LoveGrowingIt said:
I considered that, too, but didn't mention it because I haven't had my morning coffee yet.

This is great advice.

Thanks, ppfd was around 500 in centre to 420 ish outer. So have now stepped down to 380ppfd. Light is 18in from canopy.. I don't think this will hurt.

greentomatoes2025 · May 5, 2025

ArtfulCodger said:
The first thing I'd do is turn my light down a bit, until the symptoms stop increasing. It does look like you're outrunning Ca and (to a lesser extent) Mg. I'm not familiar with the nutes and supplements you're using, but it's probably worth doing some math to see how many ppms of Ca and Mg they've been getting, and adjust as needed. I'd wait on flipping until you get this sorted. Going into the stretch without enough Mg on board is a yield killer.

Thanks, ppfd was around 500 in centre to 420 ish outer. So have now stepped down to 380ppfd. Light is 18in from canopy.. I don't think this will hurt.

Thanks for your input. I'll stop in to the local hydro store tomorrow and pick some up.. cant hurt.

LoveGrowingIt · May 5, 2025

greentomatoes2025 said:
Light is 18in from canopy.

Might be a bit close. I run mine higher for wider dispersion.

greentomatoes2025 · May 5, 2025

Illbill said:
I just grew some ww/bb in coco. It was a cal-mag whore. Do you have perlite in your coco mix?

Interesting to hear and thanks for the insight! I guess after my recent flush I may have starved her a bit.

I am using a 70/30 canna mix yes.

Hope your grow went well dude. Did you experience any bud rot at all?

ArtfulCodger · May 5, 2025

greentomatoes2025 said:
Thanks, ppfd was around 500 in centre to 420 ish outer. So have now stepped down to 380ppfd. Light is 18in from canopy.. I don't think this will hurt.

Meters have their uses, but for setting intensity, nothing beats reading the plants. Every cultivar (and sometimes pheno) will react differently to different light levels. When your top fan leaves are flat, level, and vibrant green, they're digging the light. When the edges curl, they taco or twist, or you see colors other than green, it's probably too much light.

greentomatoes2025 · May 5, 2025

LoveGrowingIt said:
Might be a bit close. I run mine higher for wider

LoveGrowingIt said:
Might be a bit close. I run mine higher for wider dispersion.

Ok noted! I'll raise to maybe 24"and see how she responds. Ideally I'm hoping to stay within 25-30DLI range or around 400 ppfd/umol which from what I understand is the minimum range for late veg..

greentomatoes2025 · May 5, 2025

ArtfulCodger said:
Meters have their uses, but for setting intensity, nothing beats reading the plants. Every cultivar (and sometimes pheno) will react differently to different light levels. When your top fan leaves are flat, level, and vibrant green, they're digging the light. When the edges curl, they taco or twist, or you see colors other than green, it's probably too much light.

Thanks bro, I have noticed a bit of taco and lighter green in the last few days... sound advice thank you

Illbill · May 5, 2025

greentomatoes2025 said:
Interesting to hear and thanks for the insight! I guess after my recent flush I may have starved her a bit.

I am using a 70/30 canna mix yes.

Hope your grow went well dude. Did you experience any bud rot at all?

No bud rot at all. If you ever flush again do it with watered down nutes not plain ro water. I would get a bottle of calmag and give it a full dose every water. Mine snapped out just fine but it needs it. I would also be at the point that I was watering every day and not letting the coco dry out. I’m sure your nutes hav calcium and magnesium in them but mine wanted extra. You also flushed everything out with the ro water. Coco is a little different animal.

Am I looking at CalMag Nutrient deficiency here?

Am I looking at CalMag Nutrient deficiency here?

greentomatoes2025

JIMKSI64

greentomatoes2025

Onelife

Illbill

LoveGrowingIt

ArtfulCodger

LoveGrowingIt

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greentomatoes2025

greentomatoes2025

LoveGrowingIt

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ArtfulCodger

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Illbill

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