I am by no means an expert but you have a 400 watt light over a freshly transplanted plant in a 5 gallon hempy bucket, its planted 6" below the lip of the bucket and the top of the perlite is dry 20 minutes after u water it from the heat of the light, your humidity is probably 20% and it has no air because its buried inside a bucket. Post a pic of the set up and not the plant.