Maybe because your changing the light wave lengths on the young plant.
from sunlight to artifical the plant could be having a hard time adjusting.. you need to switch to COOL flo tubes which are higher in the Blue Spectrum...
when you stick the young plant outside right now in october the sun is sitting in the sky at a slant to where more red spectrum is shining on earth while this is good for budding not so great for vegging i would keep your plant inside under cool Flo tubes or if you want to spend extra go to any pet store and by 18,000k 4ft aquarium plant lights. in blue spectrum, it will say so on the package.
also your young plant likes nitrogen... right now your making your plant crave phosphate which aids in budding. i included a pic with a fish product i use and my plants are from a random strain as well. its nubers are 5-1-1 the first number is the nitrogen, the second is phosphate, and lastly potash.
and finally the PH level of your soil. it should range from 6.5 to 7.5 you can get a ph meter at any store that sells garden supplies heres a pic. its in the middle