Water the soil in the area you intend to use the tree dibble. Wait a few hours for the water to fully soften the ground and make it easier for the dibble to push through.
Place both hands on the handle of the tree dibble and exert downward pressure to push it through the soil. Push the tree dibble side to side and back and forth as needed to expand the hole wide enough to fit the root ball of your tree seedling.
Pull up on the tree dibble until you fully remove it from the hole. Measure the hole to ensure the hole reaches a depth approximately 1 to 2 inches deeper than the tree seedling's roots.
Pour an appropriate amount of fertilizer into the hole. Check the tree seedling's packaging label for specific fertilizing directions.
Plant the tree seedling in the hole. Push the soil back into the hole using a shovel or your hands. Pack the soil in tightly, using your hands or the back of a shovel.
Measure 2 inches from the hole and make an imprint with your finger, a rock or other object to mark it. Position the tree dibbler at a 45-degree angle toward the planted tree and push it through the soil at the marked point. Insert the tree dibble down to the same depth as your original hole. Push the tree dibble forward toward the plant as far as you can to prevent air pockets and compact the soil. Lift up on the tree dibble to remove it from the soil.
Make two more holes, repeating the technique described in step 6, surrounding the planted tree seedling. Press down the soil around the seedling with the palms of your hands or your heel to make it firm.