help with tom plants

I start my seeds of in an unheated propogater.  The seeds are all planted in pots and the pots stood in the propogator.

Of the 32 tomato seeds I planted last Wednesday 29 have germinated and they have now been moved out to the greenhouse.  I have turned on the heater to stop them getting chilly on the cold nights.

I only keep them in the propogator until they have sprouted, as soon as they have then it's off to the greenhouse as that is the only place I have a decent light level.