I built a couple large raised beds ;15X4 two feet high for my wife to grow veggies. In these boxes I filled about 2/3 full of soil from sod that has completely composted. In the remainder I blended the soil with about two yards of leaf/grass compost. Will I need to supplement with more N for vegetables with alfalfa or soy meal or is the compost enough. So far almost everything is up and doing well.