Well, I just had this problem *I think* but I can't tell if it's the same one cause the lack of pics. If it looks like my picture, though, it was because of nutrient lock. That happens when you put too much ferts on, and the plant cannot absorb any of them. Also, there could be a pH problem, so I recommend buying some distilled DRINKING (it contains some trace minerals still)water, making sure the pH is around 6.8-7.0. The fix I used was flushing the plant with 3X the pH'd water as the capacity of the pot, and then making sure it has drained ALL of the excess water out. Once the soil is dry again, water it with ONLY pH'd water for the next four times or so. After that, try only fertilizing it at about 1/3 of the recommended strength. Hope this helps! It made my plant come back but the brown spots wil never go away
. P.S. this was an early pic so it doesn't show the brown spots so much.
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