Brown spots on dying leaves?

[HeliosGrow]

Hey everyone so one of my outdoor plants has been experiencing some issues these past few weeks, i noticed that the stems on the plant turned purple and a lot of the leaves are developing these brown spots and then eventually die, does anybody know what the cause of this could be? I attached some photos of the plant, I appreciate the help!

 

[Crane]

What soil and ferts are you using? I'm definitely not an expert, but just someone who has been struggling with same kind of problems for the last year or so.

If you have been giving it a reasonable amount of fertilizer (to rule out a deficiency, purple stems and those leaves are pretty classic phosporous def I think), then it's more probably a lockout; too much fertilizer messing up the balance of the soil. I've had this in several grows and the best thing has been a flush: run something like 20 gals of water through the pot to flush out all build-up, and then resume your fert plan as normal. It takes some time to get better and the leaves already affected won't heal.

On the other hand,it is a big plant and the container isn't that big, so if you have been going low on the nutes then maybe add some P. But even then I think a flush first would be beneficial.

Maybe, the best thing if you can manage it, as the plant doesn't seem to be flowering yet, would be to repot it into an even bigger container?

Good luck.