Magnesium deficiency? Hydro

That’s over 5-7 days. Not that big of a swing.

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Here’s a picture of the roots without a flash. Like I said I’ve had whiter but they aren’t bad and are filling up this 27gal tote quick for only being in it for less than a week.

The feed isn’t dropping as fast now. Dropped 10ppm since this morning


how does affected leaves feel compared to unaffected?

More or less the same. Besides for the real far gone leaves they felt dry and crispy where the chlorosis is.

The very tips are curled down

where did it start??

It’s been happening throughout the grow. Been delaying flowering for a couple weeks now trying to sort it out.

The bigger, fatter, older fan leaves were the worst off and were distorted. These leaves are huge like 2 inch wide and at least 10 inch long fingers.

I documented the grow pretty well if you have time and an interest


oh ok sorry, ill go read into it

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do both of these ph measurements come from that same bluelab?

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No worries was just figuring maybe my journal could help someone help me.

The Bluelab combo and Bluelab doser are reading same pH. Both are calibrated regularly and the doser is brand new. The combo pH probe could use replacing, but so far only drifts 0.2 over the two weeks between recals.

Negative on the 3rd opinion. Only one I know who grows.

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from what ive learned, when it comes to this type of growing, fuck what def the plant might be showing and make sure your ph is right before adding anything to fix the def.
if youve been using that formula for 2 years with no issues, i think that we can start pointing to things such as finicky strain or recent changes to the environment or the way of measuring ppm and ph has changed.
if changes were not made this grow from the last grow and the environment is the same as the last grow (temp, rh, lighting, etc), then id say its genetics or some bitches

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Looks like a magnesium deficiency to me too. Could be ph related but i’ve been getting it a bit recently since i switched to led’s & coco. I upped the calmag slightly and that seems to have done the trick.
I remember reading a post somewhere about plants under bright leds burning through magnesium faster than expected and your fast growth rate suggests to me that’s probably whats happening here. Magnesium is mobile so a plant will deplete older leaves in favour of new growth if it cant uptake enough.

High temperatures quite often cause humidity to become too low in veg which can negatively affect a plants ability to uptake nutrients but your growth rate kind of rules that out :thinking: I’d try adding around 0.7ml/l of calmag to your res and wait a while. Leaves already affected wont recover but they might stop getting any worse :thumbsup:


too bad you can’t disconnect one & experiment on a sacrificial lamb…


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Well I took clones so ill know these are mag whores and dose them properly and hopefully have a better experience. Only way I’ll learn strains is by running them and journaling.

Ill run my nutrient #s through cannastat to figure how I can tweak my recipe to add more Mg without messing with my ratios of Ca and K too much. I wish hydrobuddy was on Android my computer died and can’t use that program anymore.

My temps and RH are pretty good.

And yeah I could always separate a plant and put it in a single tote, but then it won’t get pHed as often (no doser) and that could be a variable


your response is better than mine lol
would also explain a lot
we will see

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Well minor issues that we’re easily corrected by upping feed or making minor ratio variations. I haven’t used Epsom in my Jack’s 3-2-1 (really Jack’s 3-2) in a while actually. I only started to this grow to fix this Mg deficiency.

The temps are down a little from last grow (winter here) but within 7 degrees. RH is 50% which is what it is year round (humidifier in winter and dehumidifier in summer).

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I’m thinking we should look at raising the oxygen levels in the water.


@SquirtleSquad Did you try adding cal/mag?

Lovely looking roots though bud. Great job.

Gonna be bud city soon.



That’s a good suggestion

Hi man :blush: I grow in Coco with solstrip LED Light. I have the EXACT problem as you do with my grow. Damage is only on big fan leafes and is worst on the older lower ones. Upper leafes show golden yellow necrosis and lower leafs show dark Brown Black necrosis. All on tips.

My pH was always 5,6 and runoff as well. I also thoth about raising pH because cal mag better absorbs with higher pH. So I raised to 5,7 but nothing changed. 4 days ago a raised it to 5,8 and I doubled my Cal-mag to 2ml/L. I Hope it will get better :blush: any other conclusions? Gl! :muscle:


I added more Epsom last night but the original mix had some already. The Jack’s has 6.32% and that on its own is usually enough.

2.4g Jack’s, 1.6g CaNO3, 0.8g Epsom was my starting mix.

Anyone got a calculator for my mix? I’m getting varying results from the cannastats in web browser calculator and the dry salt Excel calculator for CaNO3.

The mix is 5% N, 12% P2O5, 26% K2O, 6.32% Mg, 8.21% S, 0.3% Fe, 0.05% B and Mn, 0.015% Zn and Cu, 0.01% Mo.

CaNO3 is 15.5% N and 19% Ca (when I enter this into salt excel calculator I get 65ppm N and 93 ppm Ca) but the website calculator gives me 66ppm N and 80ppm Ca. So I’m not sure what to believe.

MgSO4 is 10% Mg and 13% S. The differences between the website and salt calculator is even greater here.