In the past couple of years, the first half of the season has come in September and the second half added the following May. That means season 5a of The Fosters will be on Netflix in September 2017 and season 5b will be added in May 2018. That is assuming that Freeform’s library doesn’t get snapped exclusively by another provider such as Hulu or Amazon. We haven’t heard any rumors of this so far but is always a scenario to be aware of.