did you water the soil before you planted them?
did you water after placing them?
.
i believe its best to water the soil thoroughly before planting.
Let it drain out, place the seeds in and then water VERY LITTLE
after they are in there.
.
if you didnt water before planting but watered after, the seeds were
probably pushed down further into the soil, thus taking longer to make there
way to the top of the soil.
.
also try and keep the it warm and humid in the cup.
place a piece of plastic bag over the top of the cup and
use a rubber band to keep it tightly fit around it. (greenhouse method)

good luck money. -Lit