WhiteKnight, one way to improve the sandy soil is to grow a cover crop of nitrogen-fixing plants (e.g., soybeans, vetch, alfalfa, red clover, sweet potatoes) then till them in before they mature, adding wood ashes and manure if you have them. This was a technique Dr. George Washington Carver developed, and encouraged the poor southern farmers to do. Many of them, freed former slaves and poor rednecks, could only afford marginal land that had already been depleted by continuous mono-cropping of cotton, and would only grow a subsistence food crop, if that. He realized that they had no $$ to spend on commercial fertilizer, so this was one way to improve their soil without a lot of cash.
I once read (Mother Earth News, I think) the account of an engineer who lived and worked in metro-Atlanta. He bought a few rural acres, the prepared it this way: With the help of his wife and kids, he first spread chicken manure by the pickup load (free for the shoveling, if I remember correctly) at about 3/4 inch deep. Then, he covered that with at least 8 layers of old newspaper, on which he piled about 8 inches of spoiled hay (all free, or nearly so.)
This, he accomplished before Halloween, then left the field to winter over. In late spring, after checking in a few spots, to see that the earthworms were beginning to be active, he and his family went through, poking holes with a sharpened stick, through the mulch and paper into the soil, followed by seeds for corn, beans, tomatoes, and potato pieces with “eyes.” (Probably more other veggies than I remember) His harvest was huge, and he didn’t have to till the soil — the worms did it for him.
I haven’t had the space to try it yet, but I intend to (with wood ashes, too.)