or if you don't have a ready source of aged poop compost will do, or if you don't have a ready source of compost aged poop will do. I
f you have neither simply piling spray free grass clippings on the soil for several months prior to planting will help, throw in some used coffee grounds as well, some leaves as well. Give a few months for it to break down and then plant. Not absolutely scientific but better than doing nowt. It all adds organic matter into the soil that will benefit the soil. I did a raised garden last year with grass clippings, coffee grounds, some old hay, old bits of wool, paper, a bit of fresh poop & a layer of soil over the top. Left it a few months & planted tomatos into it, they did fine.
rob