Till the area around the tree roots to loosen the soil. Till about 6- to 8-inches deep.
Mix soil and fertilizer. Put a layer of about 2- to 3-inches of the soil and fertilizer mixture over the tilled ground and work the mixture into the soil with a rake. Put an 8- to 10-inch even layer of soil and fertilizer over the tree roots.
Lay sod over the tree roots, on top of the soil. If the sod needs to be cut to size, do so with a sod cutter or a utility knife, making sure to cut through the roots of the sod. Firmly press the sod into place.
Water the newly laid sod. Keep the area thoroughly watered and avoid stepping on the sod for about 2 weeks to allow it to take root.