Now that your old tree is gone, you want to plant another one in its place. Planting a new tree in the same place as an old one requires less work than planting a tree on virgin soil, in some ways. If the tree was recently removed, the soil is already excavated and only needs to be worked a little before the new tree is planted. However, if the old tree died of disease or unknown causes, the soil must first be sterilized or the new tree may suffer the same fate as the old one.
Sterilize in Summer
Loosen the soil to the depth and width of the old tree's root system. Remove any remaining roots, rocks or any other solid matter. Begin this soil preparation process in summer, at least two months before planting the tree.
Water the loosened area long enough to thoroughly wet the top 2 feet of soil.
Spread a plastic sheet over the entire tilled area and secure it with a few bricks on the edges. Leave the plastic sheet to heat and sterilize the soil for at least two months, but check every two weeks that the soil remains moist.
Remove the plastic.
Plant in Early Fall
Add 3 inches of aged compost over the loosened area of soil. If the soil level is low, add more aged compost to bring the soil back up to 1 inch above ground level.
Turn the aged compost into the soil as deep as you loosened it during the summer. This returns vital nutrients that the previous tree leached out of the soil.
Dig a hole in the center of the loosened soil that is just as deep and twice as wide as the container holding the new tree.
Place the new tree in the hole so that it sits at the same level it was when it was in its container. Backfill the excavated soil around the tree so that it just covers the root ball.
Water the soil deeply so it reaches beneath the new tree's root ball. The best way to do this is by running a slow hose at the base of the tree.