Ventilating a propagator?

I've made a DIY propagator. 

http://chat.allotment-garden.org/index.php?topic=112086.0

It's now got a door on it.  At the moment when you close the door it's pretty much a sealed unit.  Would it require ventilation?

TIA

Adri

Some ventilation is necessary because there will be some moisture in the compost from initial watering in which will condense on the top of the propagator. As seed and new seedlings don't use much water at all, you need to adjust this by letting the condensate escape so they are not too wet.