See if you can get you hands on some of that fine mushroom compost. Isn't chester county the mushroom capitol of the planet still?
Yep, Kennett Square is considered "the mushroom capital of the world", but there's also a lot of mushroom agriculture in the nearby towns of Toughkenamon, Avondale and West Grove Pa. On cold mornings in fall and winter, you'll see(and smell) large piles of fresh, super-steamy mushroom soil near mushroom houses as you drive by. It is processed, aged, limed, and eventually transported to the mushroom houses, where they may add more gypsum and nutrients. Then it's run through a machine that chops it up and fluffs it up, aerates it, and then it's left outside to compost. This naturally causes it to get really hot, even sitting outside in mid winter, causing huge quantities of steam to rise up.
After a while, it's carried into the mushroom houses, and dropped into the beds within the dark mushroom houses. Once a crop of mushrooms has grown and is harvested, ALL the mushroom soil is removed, because new mushroom crops need new soil.
But the used mushroom soil is actually optimal for growing pretty much everything else. It's "too strong" for growing most regular sun-lit crops until AFTER it's been used it mushroom houses to grow 1 crop of white mushrooms. Its only used in the mushroom houses for a matter of several weeks, then it's all removed and sold for use as nutrient rich mushroom compost for higher plants.
But even then, it sometimes needs to be mixed(diluted) with inorganic topsoil, or other organic matter. Good quality mushroom soil can make a VERY noticeable difference in plant health, productivity and growth. I once ran out of mushroom combo soil when putting in flower beds around my house, so some of the new plants I bought where planted in the mushroom/combo soil, and other plants in regular bagged soil. By summer, the plants grown in mushroom soil were OBVIOUSLY doing better than the same plants right beside them that weren't grown in mushroom soil! It was night and day!
But the quality varies, and most bagged mushroom soils are weak. If you can't easily smell it, it's not very good!