So I'm just learning about permaculture and my husband and I decided to make a mandala shaped sheet mulched bed in our garden. We followed the directions in Gaia's Garden perfectly to make a lasagna style sheet mulch. We used around 10 inches of STRAW (not hay) which I thought was supposed to be seedless by nature (I guess I should have asked this at the nursery!). Well, for some reason, after all of our hard work, we have TONS of grass from the seeds growing all over the bed. Does anybody have any advice on what to do. I really don't want to have to start over since this was a ton of work, but I also don't want a garden bed full of grass. Is there any way I can stop the grass from growing? HELP!