Magnesium deficiency??? pics

Hi everyone,
I think I have a Magnesium deficiency, but I am not sure, can any one help?
This is a white widow, three weeks old planted in coco. 400 MH, 2 feet above. I stopped giving it 1/4 nutes when I saw some burning on the first leaf set a week ago.
last night it was doing great and today I saw this
It has grayish brown spots all over two leaves. one of the leaves are twisting up. And they feel dry to the touch.
Please help!

Looks like MG deficiency to me.

It looks more like a nitrogen defiency. When a plant is lacking nitrogen the dark green begins to fade to a pale green. The brown spots are an indication that the nitro defiency has been there for a bit of time. It also means that the longer affected leaves are dieing off and they will do that. But all new growth will be dark green when the issue is resolved.

IS the coco in a blended soil mix or is coco your total medium?
What kind of nutes are you feeding the plants and what are the npk's of the nutes?

Hard to say but yea kinda looks like Magnesium deficiency. Whats your water ph?

Do me a fav check out my pics in my journal, tell me if the fert burn looked like your fert burn, mines probley way worse.

brasmith, I am growing in just coco, I germinated the seeds in rock wool first and then transplanted them into 1 liter coco. I don't think it is a nitrogen def, it does not have the symptoms for it.

Corey, the PH is around 5.6, thats why I think it could be Magnesium def but I am not sure, since it could be Potassium def as well.
My fert burn was on the first set of leaves where only the tip was burned, yours is also burned on the leaf margins.

The leaves are getting worse for every hour, here are a few new pictures. As you can see the tips of the leaves are curling and twisting up. the leaves above are also getting brown patches.

I'm not sure whats wrong so I can't treat it.

Anyone?

Azadeh said:

I'm not sure whats wrong so I can't treat it.

Anyone?

Click to expand...

a magnesium surplus is hard to achieve (rare)
so you could do what I did when I thought I had this same issue.
Add 2 tbs Epsom Salt to a Liter water that has been PH adjusted
and use as Foliar Spray.

Its not enough to hurt them but if its what they need it sure will help.
you can see the same thing (only after it got better) here:
https://www.rollitup.org/attachments/grow-journals/109213d1209467760-alt0-s-grow-1st-timer-2.jpg

be sure to only spray when lights are going to go off and be careful to not spray your bulb(s)

brasmith said:

It looks more like a nitrogen defiency. When a plant is lacking nitrogen the dark green begins to fade to a pale green. The brown spots are an indication that the nitro defiency has been there for a bit of time. It also means that the longer affected leaves are dieing off and they will do that. But all new growth will be dark green when the issue is resolved.

IS the coco in a blended soil mix or is coco your total medium?
What kind of nutes are you feeding the plants and what are the npk's of the nutes?

Click to expand...

If it was an N deficiency, don't you think it would be more yellow then that? It would have also eaten up all the reserves in itself, thus crinkling up.

Thanks Alto, after looking at your pics it seems that I have the same problem, I got some epson salt today and mixed 1/4 tbs in 1/2 liter warm water. I sprayed them two hours ago and they are already looking better.

Azadeh said:

Thanks Alto, after looking at your pics it seems that I have the same problem, I got some epson salt today and mixed 1/4 tbs in 1/2 liter warm water. I sprayed them two hours ago and they are already looking better.

Click to expand...

Glad I could be of help
as encouragement here is a shot from this morning
I removed the "burned" looking leaves as they got to the point where they were no longer doing the plant any good.
and were shading the lower branches from the light.
https://www.rollitup.org/attachments/grow-journals/113538d1210242037-alt0-s-grow-1st-timer-2.jpg
Good luck with the rest of your grow.

You would think the leafs would go more yellow if it was MG, but by the sounds of it, it was MG Def.
Love to see an update in a week or 2 or you could start a journal lol .. good luck