I... just had a look at the upcoming events.

Union, Advent, Raid, Raid, Union, Advent, Union, Raid, Union, Raid, Union, Raid, Advent, Raid.
11/14 upcoming events spend your Seeds. It might be less since originally there was three more Advent reprints in there, but Nutaku already did those. Not sure what they could replace them with, second Ixion reprint...? Unlikely...

Still, might want to pace yourself for Envy.