Yes, Minnesota only has two seasons; winter, and six weeks of bad sledding. By the middle of September leaves should be bronzed and falling off.
I'm going to repeat, check your soil PH if I had to add sulfur in NH, you can reasonably expect to need to, too in MN.
Slate on edge, half cinder-blocks, pavers on edge will all work for edging of raised beds.
You may miss the perfect storm of a dry spring and fire for decades, but nature (or a clumbsy smoker) only has to get it right once. FWIW fire helps upland blueberry. its the construction that is perishable.
Upland berry is tastier and makes better pies-jams. There is a hand rake to pick them. Your in the right part of the world to find this obscure tool.
