My Matt's have been a little slow to germinate, too. Out of the first batch I sowed only one had sprouted two weeks later...of course, as soon as I started more, the original seeds started poking up their little heads lol
In fairness, several of my varieties were a little slower than usual this year. I have no idea why. I started more seeds of everything, and now ALL the seeds have decided it's time to sprout. So, as usual, I'll have lots of extras this year....something I promised myself I would avoid this year
Good luck!
Jennifer