This is my first year starting seeds indoors. Of 24 leek seeds planted, only three have germinated so far (5 days ago). I'm using peat pellets, a heating mat, and a dome. Since the first sprouts came up, I removed the dome and turned off the mat. Someone suggested to me that my conditions made it too warm for leeks to germinate. I also tried a few seeds in some peat pots with Jiffy mix thinking maybe the peat pots were too compacted, but none of these seeds have sprouted.

Any thoughts?