Here in South Florida, they can go a lot longer. Outdoor here is not so much dependent on time, but more on hours of daylight. They can take forever to finish sometimes. as daylight hours hover around 12 for much of the Summer, and some strains need quite a bit less than that to shift. I haven't grown SD in a couple of years, but I have some Sweet Tooth that will probably go until well after Oct. 1, and they say it can finish in as little as 7 weeks outdoor, but it definitely doesn't apply here. It has been flowering for almost 3 months and still has a ways to go.