labifleanswered grow question 6y ago Hey gardener! 20 weeks is long, but some sativas can take 6 months to flower, so it can get difficult to manage. Maybe with more light they would have taken less time to flower. In any case, it really looks like a sativa and it reminds me of a local strain that my roommate tried to grow, but after 2 months of flowering, he tossed it since it kept growing.