Rainbow, as I think I have mentioned to you before, Brug seeds can be a pain in the .... I planted 18 seeds this year. Not one has germinated. None. My experience has been hit and miss with them. Though I do have a 7 foot plant in my basement that started there from seed 2 years ago.
If you were aluding to having a plastic dome on the tray, most of what I read says to not use them on Brug seed and I don't.
I have had much better luck with Datura. I usually get near 100 % and they germinate fast.
Good luck.