They should germinate fine without the plastic lid - just keep the soil moist.

I bought the propagator with lid & heating mat. I used the lid in early winter because it raises the temperature in the tray. In early spring, I took off the lid, but the pots with seeds had clear plastic wrap over the tops held in place with a rubber band.

Are you having germination problems problems Alistair?
Most hardy annuals will be OK without a propagator. I haven't experimented to see whether they do better in or out of a propagator though.

I have never used a propagator and my seedlings spring up like nobody's business. I use a table in the back bedroom.

..... Bathgate, do you get enough light on the bedroom table for seedlings? Any time I try that, they go leggy and reach for the window.

Plastic lids are rarely necessary . . . seeds just need moisture, warmth and light to germinate.

Sorry I meant a tray with a clear plastic lid ....My germination success is often poor I think the seeds are rotting especially chrysanthemum conarium I see them self seeding themselves by poor soil pavements but when I try to replicate my clay soil won't have it so I try to germinate myself myself in modules with or without lids I find both have poor success rates along with a lot of other unusual seeds I buy from the net.

Soph- Yes, the back bedroom is south facing with a double picture window. The table is right up against the window so they get full on sun. It's important to rotate the seedlings 1/4 turn each day so they grow straight. Open the window bit for fresh air.