Site selection is perhaps the most critical in planting a black walnut tree. The area must be well drained of all moisture and yet, not be prone to holding stagnant cold air, also called frost pockets. The soil must also be very deep as the black walnut will protrude a deep taproot from the root system. Consult your local agriculture extension service as many plants cannot tolerate the black walnut tree. Black walnuts not only produce edible nuts, but the dark rich hew of the inner timber make it an extremely valuable wood for furniture and cabinet making.
Remove all over growth from the planting area. New black walnut saplings will need as much space as possible for new growth. Overgrown grasses and brush will create unwanted competition for the new trees.
Place the marker flags in the location which the new trees are to be planted. A good spacing rule, if you are planting multiple trees, is to keep 12 feet between each tree and rows of trees. Lay out a grid in a 12-foot by 12-foot pattern.
Dig the holes for each tree using the shovel. Make the tree holes at least 3 times larger than the root ball of the young sapling. It is better to have a larger hole than is required. The loosened soil around the small tree roots will aid in the growth of the tree.
Remove the black walnut sapling from its growing container. Set the tree into the dug hole. Keep the topsoil line of the sapling in line with the surrounding ground level. Backfill soil around the tree roots.
Tamp the soil around the young tree roots with your hands. Form a soil ring around the tree with excess soil from the dug hole. This soil ring will aid in retaining water for the young tree.
Water the young tree with up to 5 gallons of fresh water. This will remove air from around the tree roots. Keep the marker flag next to the tree to identify it when surrounding grasses or brush may exclude the young sapling from sight.