They absolutely do need to planted immediately!
It may be possible to leave s seed head uncleaned and store in the fridge for a few weeks maybe longer, the seeds are coated with a membrane that helps keep them moist, slimy really, and it inhibits germination, once remove they spout fast, or dry right up.
Aroid seed varies is size and the bigger seem to last a little longer.
Generally if conditions aren't stable and ideal, chances of success are low.
