Leaves Going Brown

[flytier]

Hi fellow potheads,

My White Widows are about 2 weeks into their 12/12 cycle with buds just starting to form and they are getting some brown on the leaves. I'm aware that something like this is normal for flowering plants, but it seems kind of soon.

They are in an unventilated closet-sized alcove at about 24 deg C in potting soil. I'm feeding them a rotation of molasses, coconut water and Epsom salt. Lighting is mostly CFL with some LED floodlights as well. The lighting hasn't been a problem so far, so I'm ready to cross that off the list of potentials.

If anyone can offer any ideas as to what it may be, it would be highly appreciated. I picked a couple leaves off without much of a thought, but they keep popping up and it now has me concerned.

 

[Suntana]

Looks to me fly like it needs calcium and the slight blistering between leaf veins could be a little to much magnesium.

 

[Canresearcher]

Check how wet your soil is. It looks to me like root tip burn ( also called leaf scorch) from excessive watering or possibly high nitrogen.
Allow the soil to dry out a little before watering again. The soil in the picture looks quite wet.
Magnesium Sulphate does not burn plants. I've used it many times ( even as a conc. foliar fertilizer) and have never had this happen.

 

[Suntana]

Take a better look Canreseaher not all tips are showing tip burn but mid way through the leaf, Molasses- high in magnesium then adding Epsom salts to the mix, I've seen it before and if you are right the last thing he should do is let the pot dry up. A good flush then let it dry out and water less more frequently. Cheers

 

[Suntana]

Also fly I did not mean the burnt area were caused from magnesium. I said the slight blistering between leaf veins (new growth).

 

[flytier]

Looks to me fly like it needs calcium and the slight blistering between leaf veins could be a little to much magnesium.

So what would be a good safe source of calcium?

 

[flytier]

Check how wet your soil is. It looks to me like root tip burn ( also called leaf scorch) from excessive watering or possibly high nitrogen.
Allow the soil to dry out a little before watering again. The soil in the picture looks quite wet.
Magnesium Sulphate does not burn plants. I've used it many times ( even as a conc. foliar fertilizer) and have never had this happen.

The root tips themselves for the most part are pretty good. I've dealt with nitrogen burn in the past and this looks different. I've used MgSO4 in limited amounts, but I tend more toward molasses for stuff like that.

 

[flytier]

Also fly I did not mean the burnt area were caused from magnesium. I said the slight blistering between leaf veins (new growth).

So should I maybe back off on the molasses?

 

[flytier]

Check how wet your soil is. It looks to me like root tip burn ( also called leaf scorch) from excessive watering or possibly high nitrogen.
Allow the soil to dry out a little before watering again. The soil in the picture looks quite wet.
Magnesium Sulphate does not burn plants. I've used it many times ( even as a conc. foliar fertilizer) and have never had this happen.

So MgSO4 would be a good substitute for a hit of molasses in my nutrient rotation?

 

[Suntana]

Fly I would back off using Epsom salts if you prefer molasses, dolomite lime is the best source of calcium in your case. You can also make a homemade concoction, egg shells and a bit of vinegar put in blender and blend it real well. Mix that into your regular feed.

 

[Suntana]

The best option in your case to combat the deficiency quickly is dolomite lime or liquid cal/mag if your close to a garden store. Your magnesium is very minor so don't worry much about that. Everybody always jumps on the over watering and I also don't believe it's over fertilizer leaf tip burn. That always starts on pretty much every leaf and works its way in.

 

[flytier]

Don't really use the Epsom salts that much anyway. Just tried it a couple times.

 

[flytier]

We don't have a gardening store per se in town, just a nursery greenhouse and a flower shop. Other than that it's Walmart gardening dept. and the like. But I can look around and see what they have. As for watering, I do it by the finger-in-the-soil-and-lift-the-pot thing and go from there.

 

[Canresearcher]

Take a better look Canreseaher not all tips are showing tip burn but mid way through the leaf, Molasses- high in magnesium then adding Epsom salts to the mix, I've seen it before and if you are right the last thing he should do is let the pot dry up. A good flush then let it dry out and water less more frequently. Cheers

No one is asking to let the plant completely dry up... allow the soil to dry out more a little before watering is exactly what I am saying--- ie. water less frequently . Magnesium doesn't create this kind of effect on leaves. The dead giveaway that you are dealing with a kind of scorch is the leaf tips. I've seen plants growing in Magnesite rich soil The discolouration of the leaves is either due to overwatering, (not enough time to dry out between waterings or excessive Nitrogenous compounds (Urea/Ammonium). Growing on excess Mg causes the entire leaf blade to become chlorotic and somewhat yellow green (not burnt as this photo shows). This is due to Ca lockout as the Mg+ starts replacing the Ca+ (seeing as they are so closely related on the periodic table Alkali metal vs Alkaline earth) ion exchange through osmosis.

 

[flytier]

Ok, well less frequent waterings isn't a problem. I can go by the way I've been doing it all along and wait another day or two with the itchy trigger finger. I've just gotten it this far and I don't want to mess it up now. Thanks for the advice, for sure.

 

[Suntana]

No one is asking to let the plant completely dry up... allow the soil to dry out more a little before watering is exactly what I am saying--- ie. water less frequently . Magnesium doesn't create this kind of effect on leaves. The dead giveaway that you are dealing with a kind of scorch is the leaf tips. I've seen plants growing in Magnesite rich soil The discolouration of the leaves is either due to overwatering, (not enough time to dry out between waterings or excessive Nitrogenous compounds (Urea/Ammonium). Growing on excess Mg causes the entire leaf blade to become chlorotic and somewhat yellow green (not burnt as this photo shows). This is due to Ca lockout as the Mg+ starts replacing the Ca+ (seeing as they are so closely related on the periodic table Alkali metal vs Alkaline earth) ion exchange through osmosis.

Glad you admitted calcium is a problem lol, backing off magnesium and adding some calcium would benefit his plants. At no time did I say the burnt issue was caused by magnesium. I agree with what you said above.
Have a great day .

 

[Suntana]

Ok, well less frequent waterings isn't a problem. I can go by the way I've been doing it all along and wait another day or two with the itchy trigger finger. I've just gotten it this far and I don't want to mess it up now. Thanks for the advice, for sure.

Do you know if your molasses is unsulfured? If it is a sulfured type it could be lowering the ph of your soil causing calcium to be locked out. Seems if you have not been using a bunch of Epsom salts and molasses has Calcium and magnesium the ph of your soil could be an issue.
Not even going to touch the over water claim, you seem to have got that message emphasized.
Just brain storming, if we all work together we might figure this out.
Peace fly .

 

[Suntana]

Something I didn't know fly is coconut water also has a fair magnesium count, maybe with all those combined that could be the reason your mag is beating out the calcium.

 

[flytier]

I made sure I got unsulphured molasses. I guess I don't even need to use the Epsom salts then between the molasses and coconut water. So you figure it may be a pH issue? I'll have to break down and see if Walmart has a test kit. Would an aquarium kit work? I may be able to get one of those there.

 

[Suntana]

Sure will but you will have to do a slurry test. It's not hard and there is lots of info online about how to do it. The molasses is on your side with the calcium in it, but I'd quit Epsom all together. I don't know if you have a ph problem for sure but definitely Calcium def. The rest of the plant looks ok.
I just thought the possibility of a ph problem may exist, a lot of the times deficiencies can be corrected by adjusting ph.
When I have Calcium issues show up I add more and insure the ph of the medium hasn't run wild for some reason. You should ph the feed going in anyway, I just assumed you were. Just use the aquarium kit they work for what your doing.