Sweetcorn (again sorry) germination time?

As I had 100% success rate in pots last year, I did the same again. they are in Richy's paper pots in an unheated propogator (in a very sunny dining room and not a million miles away from the radiator).

So I have had 4 come up in about a week and the paper pots are looking a bid furry in places, are the rest (of the 25 I sowed) done for?   After last years success I never knew s'corn could be unreliable, I would resort to the pre-chitting method but I only have another type of seed left (last years left overs - mybe more successful)

hmph!

24 hours in an airing cupboard!