Margaret, when the bloom shrivels up you should see the seed pod swelling quite rapidly. If you don't see quite a difference in say 4-5 days then cut it. I don't remember how long to maturity but a lot is going to depend on temps., light, etc.... I was growing mine outside in the ground in S. Fl. zone 10 & those seed pods developed pretty fast & matured I'm going to say within a month. Actually I think it was less time than that --- perhaps even as little as 2 weeks but I never timed it or kept a log.
