Thanks all for your responses. I've heard from landscapers around here that it's fairly awful to have had so much soil hauled away, and a big problem to have only clay subsoil. I want yo plant a mindfully planned garden with fruit trees, edibles, flowers for cutting / pollinators / hummingbirds / butterflies. Apparently roots will get stumped at the subsoil if it's not properly attended to and will die? I love the hay idea, but I don't want a hay lawn. It's a small yard - 35x40, that will have many jobs. I don't have space to create my own compost pile, though we are lookin at a contained backyard composer. Rats are definitely an issue. Any idea what all this means?