Brown spots - magnesium deficiency or fungus? Pics!

Xschtar

Active Member
I have the exact same problem as these two guys:

https://www.rollitup.org/marijuana-plant-problems/51407-what-causing-these-spots.html
https://www.rollitup.org/marijuana-plant-problems/51588-rusty-twisting.html

My leaves are rusty yellow/brown, twisting and the stem is purple on the affected clusters. The growth is slowed and the affected leaves are "begging for magnesium". For several days I've been spraying them with epsom salt but they are not getting better, and now the newer leaves are also affected. So whatever it is, it's spreading! The older leaves are the worst. It seems exactly like a magnesium deficiency (though there should be no nutrient lockout), but now I think it might be fungus. It's actually been like these for weeks now.

Merciless58 has adviced the two other guys above that it is indeed fungus. But then I don't understand, how can the symptoms be the EXACT same symptoms as MG deficiency - and how can the older leaves be affected first, the affected stems purple, and the plant affected with perfect symmetry? And doesn't fungus look completely different than this?

PH is around 6,5
Humidity 50%
Temp 24 degrees Celcius
No overfeeding, nothing added yet except for water at PH 6-7
In veg period for 40 days now (slow growth)
The seeds are from GreenhouseSeeds.nl.

HELP!!!
 

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cookin

New Member
yeah, that seems pretty similar too mine! Thats what I thought about the older leaves as well, surely it should be a deficiency then. I have two plants with purple stems but not on all of the affected ones:confused: Do you get some sticky glossy stuff developing on yours?
 

Xschtar

Active Member
Sticky glossy stuff? Hell no, my affected leaves are dry as shit and some even break because they are so stiff!

But then again, I keep spraying them with water/epsom salt so I wouldn't know.
 

Smitty750

Well-Known Member
Xschtar Thanks for the reply. My plants are also Greenhouse Seed Co. Lemon Skunk, I am starting to think that its not a MG Def but a MN Manganese Def. MG Def starts more towards the leaf edge and works its way inward. MN Def are tiny yellow brown necrotic (dead) spots in between the veins of the leaf, sometimes the vein in the center starts to yellow as well. My stems are not purple they are green and starting to take a "wood" appearence. I dont beleive its a fungus problem its affecting none of my healthy Greenhouse Seeds just 1 of my bagseeds, and 2 of my Paradise Seed Co. Amsterdam Flame. Ive ruled out the fungus problem, raised my lights just to be safe. Ive been running epsom salts for 2 days now also foliar feeding with epsom and slow if any results have taken place. Are you running Hydro or Soil. Also Im still new at this but maybe youre plants want some nutes?
 

Xschtar

Active Member
Thanks for the site, really useful! I think we can both agree it's NOT fungus. Then the question is, what is it? I have noticed that the new growths are sometimes lime-yellow-green-coloured, I have also noticed purple stems on the affected branches, and the brown-yellow "necrotic" spots on the leaves - and slow growth! I'm running high quality soil. My water is PH 8,1 so I add PH Down to get it down to a little over 6.

I checked the site and found nothing about MN deficiency. Never heard of it either. What could cause something like that?

I think epsom salt will not help you, I'm pretty sure it didn't help me! I've used like 20 grams of epsom salt now, to no avail. It's just getting worse :(
 

panhead

Well-Known Member
When you see lime green leaves do they seem stunted or too small as well as the abnormal color.

The whole leaf is lime green isnt it,not just spots on the leaf or around the edges but the entire small leaf,correct ?

Normally lime green means a nute deficiency,a zinc deficiency to be precise,get some good fert that has trace amounts of all the minors like zinc & iron then mix it up about 1/16 of the amount on the directions with ph'ed water,spray your plants when the lights are out,repeat every other day,on the odd days use only ph'ed water to mist with,keep this up & within a week the lime green should be gone.

Dont forget to use the new ferts containing Zinc in your soil also,Peters 20/20/20 is an excellent fert & contains all the minor elements.

And btw,stop spraying with epsome salts asap,its not working,when something you try has not worked after a day or two you should not continue using the same tactic,get the zinc & you'll be tight.
 

Smitty750

Well-Known Member
Agree Light green or lime green leaves is normally a sign of a zinc def. MN gets locked out if youre MG levels are too high or if youre PH is to high it has a tendancy to lock out trace elements and minerals like MN,MG,Iron,zinc,copper etc but NPK is absorbed better. A lower PH will promote better trace mineral absorption but reduces the amount of NPK available. You gotta kind of find a happy medium. Try doing a flush with a PH in the middle like 6 for soil. Than start nutes and keep and constant PH if possible. If you think its an MN DEF try running a lower PH to boost mineral uptake. Check this out

GROWFAQ
 

Xschtar

Active Member
But damn, if it's zinc and MN deficiency, haven't I just made it worse by adding like 20 grams of epsom salt to the soil/plants? I try to water with water with pH 6,5, shouldn't that be enough to catch all the minerals? Sometimes the soil dries up, I don't have any verlicolite and no leca but it's the best quality soil. How can I now get it to absorb MN, the MG will never go away, won't it? How acidic water should I water with, pH 3-4?
 

jondog123

Well-Known Member
But damn, if it's zinc and MN deficiency, haven't I just made it worse by adding like 20 grams of epsom salt to the soil/plants? I try to water with water with pH 6,5, shouldn't that be enough to catch all the minerals? Sometimes the soil dries up, I don't have any verlicolite and no leca but it's the best quality soil. How can I now get it to absorb MN, the MG will never go away, won't it? How acidic water should I water with, pH 3-4?
no no no, you dont want ph water of 3-4 it needs to be at least 6 with soil. Flush your soil and then add a regular dose of epsom salts and see if that takes care of the problem. I doubt you have a zinc def. those are pretty rare, its a trace mineral for your plants. :joint:

By the way I have a similar problem on a few of my plants. I will let you guys know what I find out about it.
 

Xschtar

Active Member
Well, it seems like the only thing to do is to keep watering with water at PH 6,5.... I dare not add more epsom salt, just hope a good pH will clean this up. Maybe I should water more often, so the soil does't dry out (higher pH).
 

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groprofosho

Well-Known Member
i think its actually nute burn, but its only happening to certain leaves. Im not seeing the typical tip burn of most nute burn cases. If you burn just a few roots this will happen. If i were you i would flush with ph balanced water (6.5 for soil) Then keep ferting them normally. I do hydro and noticed if i splash concentrated ferts on the roots accidentally the leaves being fed by those roots will have similar issues. Does your soil drain well? The ferts might be building up in pockets of your dirt and burning the leaves.
 

cookin

New Member
Sticky glossy stuff? Hell no, my affected leaves are dry as shit and some even break because they are so stiff!

But then again, I keep spraying them with water/epsom salt so I wouldn't know.
Mine just start off with the sticky stuff, the older affected leaves are dry and brittle
 

williewill420

Well-Known Member
I just went thru a problem looked very similar to this. Turned out I had a nutrient lockout from this grow medium I was using ( just- rite xtra ). I was having a boron defiency. I transplanted outta that just-rite, bare naked roots and all and put into a pot of bx-pro mix. I foliar sprayed it with EYEWASH, 1 teaspoon per gallon. The messed up leaves never got better they just died and fell off but the problem stopped and now it is doing strong. It looked just like your problem. If your growing in soil that has a ph higher than 7 theres good chance gonna be a boron def.
 

snutter

Well-Known Member
I have the exact same problem as these two guys:

https://www.rollitup.org/marijuana-plant-problems/51407-what-causing-these-spots.html
https://www.rollitup.org/marijuana-plant-problems/51588-rusty-twisting.html

My leaves are rusty yellow/brown, twisting and the stem is purple on the affected clusters. The growth is slowed and the affected leaves are "begging for magnesium". For several days I've been spraying them with epsom salt but they are not getting better, and now the newer leaves are also affected. So whatever it is, it's spreading! The older leaves are the worst. It seems exactly like a magnesium deficiency (though there should be no nutrient lockout), but now I think it might be fungus. It's actually been like these for weeks now.

Merciless58 has adviced the two other guys above that it is indeed fungus. But then I don't understand, how can the symptoms be the EXACT same symptoms as MG deficiency - and how can the older leaves be affected first, the affected stems purple, and the plant affected with perfect symmetry? And doesn't fungus look completely different than this?

PH is around 6,5
Humidity 50%
Temp 24 degrees Celcius
No overfeeding, nothing added yet except for water at PH 6-7
In veg period for 40 days now (slow growth)
The seeds are from GreenhouseSeeds.nl.

HELP!!!
You are nutrient deficient. you need to get the 3 basics (N P and K) to these plants asap.

Good luck..
 

snutter

Well-Known Member
i think its actually nute burn, but its only happening to certain leaves. Im not seeing the typical tip burn of most nute burn cases. If you burn just a few roots this will happen. If i were you i would flush with ph balanced water (6.5 for soil) Then keep ferting them normally. I do hydro and noticed if i splash concentrated ferts on the roots accidentally the leaves being fed by those roots will have similar issues. Does your soil drain well? The ferts might be building up in pockets of your dirt and burning the leaves.
This is definitely not nute burn. Nute burn has a different look and will start at the edges of the leaves, or the tips... I'm pretty sure it's a nute deficiency. I'd feed them asap. But don't go overboard. Don't go giving them more nutes then recommended just because they're deficient. that will lead to nute burn...
 
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