Board Thread:Plants vs. Zombies 2: It's About Time/@comment-24204889-20140803045340/@comment-5792287-20140804171255

50 worlds won't happen. That would equal HUNDREDS of plants. Which would also make the Endless Zones incredibly hard because it would mean that it would take hundreds of levels before you could get the sun card every level.

They said that they had originally thought of about 50 different time periods, but they never said they'd use all of them.