The growths of terumah are terumah. And the growths of those growths are chullin.  But tevel, maaser rishon, after-growths of the she-mittah year, terumah from outside the Land [of Israel], meduma, and bikkurim — their growths are chullin.  The growths of hekdesh and maaser sheni are chullin, and he redeems them at the time of their seed.