Stonerdanswered grow question 4 years ago Beautiful plants you've got there especially for first grow!! From the looks of it seems like your plant is suffering from a light deficiency, Nitrogen (N) most likely, if you could give more info about their diet, which fertilizers you're using, and a picture of the yellow leaves on the plant to see if its at the top or bottom of the plant that'll help determine that more precisely.
Good luck and happy growing :)