Really confused about why this works..

[Nickerly]

I sowed a load of seeds in paper last weekend and covered them with plastic bags and put them by a warm radiator but nothing has sprouted up yet. But when I 'planted' the same seeds on wet kitchen roll and put them in a plastic bags they sprouted after a day!

Why does this happen? Why do the plants seem to prefer wet paper towel to lovely moist soil?

[Nicos]

Cold potting compost????
If I remember, I try to warm up the bag of compost by bringing it into a warmish area and then water in the seeds with warm water...It does speed things up a bit!