If you have seeds that need to germinate
in the dark then just place sheets of newspaper
on top, Seeds that need extra warmth as
well as darkness to germinate can be placed
in your airing cupboard if you have room.
If you have money to spend you could purchase
a heated propagator for inside your home
It's a good idea at this stage if you water
in a fungicide to help prevent damping-off
Note To assist germination and establishment
you can before sowing large seeds soak the
seeds in water for 12 to 24 hours.