OK, I messed up and three months ago put some black plastic down to kill an area (for a pocket wildflower meadow, Illinois) without doing any research. I now know the main thing I didn't do was cut the grass short first. However, I was smart enough to use thick 6mil plastic. And I did anchor it all around with boards and bricks. I've since checked out videos and see that some people don't cut back the grass, so I hope that won't be a problem. Here's what's got me worried: I just now lifted a corner of the plastic (it's late Sept) and even though it's been in place since June over a long hot summer, and even though most of the grass is chalky light brown, it is interspersed with some light green blades. Is this normal, or did my sheeting not work? In my mind I was hoping I'd see bare dirt, all the organic material having rotted away.

Or is this what I should expect since I didn't cut it down short? Could it be that the black plastic worked? That'd be great to hear. (I should add that I don't expect to actually lift it for another month, after the first frost.) Also, if this is workable, is it just a matter of raking off the grass that's here? I know wildflowers like a depleted soil and would rather not have nutrients added. But maybe this grass doesn't have any nutrients in it anymore. Thanks for any information or thoughts!