Hand-pull any weeds surrounding the walnut tree area. Press a spade next to the base of weeds to lift them from underneath.
Break up the soil around the walnut tree with a garden fork. Avoid using a tiller. The walnut tree may have a shallow root system, though most have deep taproots.
Broadcast your blue fescue or Kentucky bluegrass seed in the early fall. You can distribute blue fescue at a rate of 6 to 8 pounds per 1,000 square feet. Kentucky bluegrass can be distributed at 2 to 3 pounds per 1,000 square feet.
Cover your grass seed with 1/2 inch of compost. Rake the compost so it completely covers the grass seed to prevent birds from picking off your seeds.
Water the area thoroughly so the ground is moist. Keep the ground moist for the first two weeks by spraying the area with a mist of water three times a day.