Fusionanswered grow question 5 years ago Could be the strain. Dark leaves could be a sign can give it more light as well. Measure your lux if don't have a light meter can download an app for your phone. "Lux light meter" in play store , it's free.
Seedlings 5,000-10,000 lux
Veg 15,000-35,000 lux
Flower 45,000-100,000 lux