After the flower is done blooming a fruit that looks like a green brain should start to develop the seed is in that.

Well, - does the seed always develope? :) Arum

I don't see any seed pods on ANY of my nasturtiums, and they have been blooming for a while. I have some HUGE plants, thanks to my dog (he ran away with a pkg of seeds from Dollar General and spread them all over the yard. Now they are growing everywhere and, wouldn't you know it, they look bigger and better than the ones I planted in my flower gardens!!!) Anyways, how long does it take after the flower dies off before the seed pod appears? Will it be later in the season, or are they just not getting pollinated?

It takes a couple of weeks for the seed pod to develop after the flowers have gone by. The "brain" shaped pod will turn brown & the seeds are in it. They will reseed naturally if left alone. The seed pods will fall off & start new plants for next year.