What kind of deficiency is this?!

I started seeing these darkish purplish spots around the edges of a lot of my leaves and it's been leaving me super concerned. I don't understand how this is happening especially since i'm using MG potting soil. This is my second grow with mg and this didn't happen the first time. I was thinking it was somekind of phosphorus deficiency but im unsure because this is my first time see this. How quickly can i solve this? it's outdoor and has started flowering.

thanks

You're right, looks to be a phos deficiency but also looks like it could be a magnesium deficiency.

Need more info though. What is the PH of your water? Have you checked the PH of the soil? Have you flushed? etc

I use straight tap water, I was worried about pH because I thought it would prevent certain nutrients from being absorbed. I flushed once on accident from watering too much at one time. I'm not sure if it can be calcium deficiency because i mix in eggshells to the soil to increase calcium content.
Is there any way to quicken the recovery process for my phosphorus deficiency? and how?

Mild nute burn from the N in MG soil is my best guess. Do not feed! cn

what the bear said..................

are you sure its nute burn? the leaves that have this purple brown thing don't start burning from the tip as normal nute burn I have seen. It's widespread all along the edges of the leaves. doesn't this rule out nute burn?

genuisgeek said:

are you sure its nute burn? the leaves that have this purple brown thing don't start burning from the tip as normal nute burn I have seen. It's widespread all along the edges of the leaves. doesn't this rule out nute burn?

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Filter and PH your water. Any rain will have 0 salts and a neutral PH, but if you're watering with tap water it could have a PPM of 250+ easily and a PH of 8 which can lock out any nitrogen and magnesium. Take care of that and your plant will bounce back.

I agree too..
Nute burn. Slightly.