Germinated tree seedlings are grown best when slightly coddled for a year or two before being planted out into the garden soil. Young tree saplings of a year or two in age are in a better position to stand up to the elements in unprotected outdoor settings and go on to mature into healthy full size trees.
Fill a 6 to 8-inch nursery pot with a lightweight easy draining sterile potting mix. Create a hole in the center of the pot larger enough to accommodate the tree seedling and its surrounding soil intact.
Plant the seedling in the soil at the same height and very gently compress the soil around the roots so that there is good soil to root contact.
Water your potted seedling deeply at planting time and maintain evenly moist soil, never allowing the planting medium to become dry.
Place the seedling and its pot in a location that receives bright direct sunlight indoors or a protected location outdoors.
Feed the seedling with a balanced, complete water soluble houseplant fertilizer formula with a guaranteed analysis of 10-10-10. Apply according to product label directions at least once per month and do not over-fertilize, which can cause rapid but weak growth.
Transplant the sapling into a larger nursery pot as needed when the roots fill the pot and start to circle the pot.