Inspect your seedlings to make sure that they are ready to plant. They should be at least ¼-inch long, preferably 3/8-inch in diameter and 1 inch above the root collar. Be sure to plant your seedling before bud break.
Dig a small hole no deeper than two inches in diameter. Make sure the bed you plant the walnut seeds in is not too dense. Plant on average only six seedlings per square foot. Plant only seedlings that have more than five lateral roots.
Cover up the soil above your seedlings with cloth with ordinary mulch on top to keep it secure. Use fencing to keep out predatory squirrels or birds. Keep the soil moist, but don't over-water. Remove the cloth in the spring.