Several years ago, I bought seeds for mache, a French green. I raised some in the fall and liked them a lot. For the past 4 years, I have planted mache seeds in both the spring and the fall and I have never had another mache seed come up. Why? I have been gardening for 40+ years.
Certified GKH Gardening Expert
I really don't know unless the seeds are not viable. While these can be finicky when it comes to germination, you should still have gotten something. And since you've been gardening this long, I would think the soil and growing conditions for this plant are being met. Very unusual. I wish I could be of more help, but all I can think of would be the seeds or the soil. You may want to try a soil test to see what this turns up.