Brown spots on leaves

Lstndasauce

Member
Is this leaf septoria or a calcium or magnesium issue? Or something else? Strain is lsd auto in soil under 250 watt hps about 16-18 inches above the canopy and its in about the 3rd or 4th week of flower. Been using scotts super bloom nutes at 2/3 strength and little epsom salt every 2 or 3 feedings. The first two pics are yesterday and the rest are today about same time. Percentage of leaves affected seems to have tripled. Any info is greatly appreciated.
 

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Red Eyed

Well-Known Member
Resembles a calcium deficiency however, may also have a slight phosphorus def. as well in there. Info on the grow?
 

Bernie420

Well-Known Member
Is this leaf septoria or a calcium or magnesium issue? Or something else? Strain is lsd auto in soil under 250 watt hps about 16-18 inches above the canopy and its in about the 3rd or 4th week of flower. Been using scotts super bloom nutes at 2/3 strength and little epsom salt every 2 or 3 feedings. The first two pics are yesterday and the rest are today about same time. Percentage of leaves affected seems to have tripled. Any info is greatly appreciated.
looks like P deficiency to me
 

xtsho

Well-Known Member
Scotts Super Bloom is 12-55-6. That's way too high in phosphorus. It's also lacking in micronutrients, calcium, magnesium, and sulfur. It's basically just ammonium phosphate, potassium phosphate, and a touch of iron. It's more of a booster for flowers and not a complete fertilizer.

I think your issue is due to the high levels of phosphorus causing nutrient antagonism and locking out other nutrients in the soil. That and the fact that you're not feeding your plant many of the nutrients it needs with the exception of magnesium and sulfur from the epsom salts. It's best to use a balanced fertilizer throughout the entire grow. Just because it says super bloom doesn't mean that it's all you need when the plant starts flowering.

The stage of flower that plant is in is when you'll typically start seeing issues if it's not fed properly. Unfortunately it's also a little too late to get it as healthy as it could have been had it been fed properly to begin with. I'm not saying you can't get a decent harvest, I'm saying it could have been better had you fed a balanced feed throughout the grow and not used only a high P fertilizer.

What to do about it? Cut back on the P and get something that is more balanced and has micronutrients, calcium, etc... Something like FloraNova Bloom, MaxiBloom, etc... which is just one product and will provide the plant with everything it needs at this stage.

Good luck
 
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