hey dude, my guess is too much water, fertilizer. just use distilled water (if you already fertilized it) for a while, and let that soil dry more if it's saturated all the time, and make sure the medium you use drains well out the bottom, otherwise it will be hard to flush nutrients when you need too. plus did you have a light too close to it, or...? it might've got overheated a bit. just my guesses though dude, peace.