I live in Southern California near the Mexican border where the desert is VERY hot and the soil sandy. I want to plant some citrus trees (grapefuit, lime, oranges) around my property. There are already some citrus trees planted and they seem to be doing well as long as they receive plenty of water. I also notice that citrus trees from local nurseries have them bundled up in burlap with sand. My question is: Is sand an ideal soil to plant the trees or should I put in another type of soil once I dig the hole and plant them? Also, what nutrients should I give them and when?

Any advice would be appreciated! Thanks!