Judging by the fact that your plant looks like mine did at that size, my guess is that you're over watering and possibly overfeeding?

-The brown tips tell me you're getting nute burn.
-The stunted growth tells me you've hit nutrient lockout.
-I'm having trouble putting this one into words, but just the way your fan leaves look make me think you're over watering.

I would wait until the soil is COMPLETELY dry for the first 3 inches down or so. when I started following that rule, I only watered every 3-4 days, feeding every other time, and my stressed plants literally fixed themselves in under 24 hours.

I also can't tell what your soil looks like because of the emergency blanket, but do you have drainage in your soil mix? like maybe 25% perlite or more? If your soil mix isn't draining properly, you're going to see this problem reoccuring. You also might be increasing your risk of root rot and mold.

Keep in mind i am in no way an expert, This is just the experience i've had with my grows. good luck :stoned: