Rooting a cutting from an orange tree is far less common than grafting the cutting to a compatible rootstock. Although there are some varieties of orange trees that will root from cuttings, a far more reliable way of rooting and propagating an orange tree is by air layering a cutting. In air layering, you root a branch on the tree before you cut the branch off for transplanting.
Make two circular cuts 1 1/2 to 2 inches apart completely around a relatively young branch of a donor orange tree.
Make a straight cut along the branch between the two circular cuts. This cut should connect the two circular cuts.
Peel the bark off the branch to expose the underlying wood.
Soak sphagnum moss in water until it is completely saturated.
Take the moss out of the water and squeeze the excess water out.
Wrap the tree wound with a handful of the wet sphagnum moss.
Wrap the moss ball with clear polyethylene sheeting. Roll the edges together to make a tube about the size of the ball. Seal the rolled edge with electrical tape.
Pull the two ends of the tube tightly around the branch on either side of the moss ball and seal the edge to the tree with electrical tape. Make sure to seal all openings to help keep the moss moist.
Cut the branch from the tree when you see roots on all sides of the moss ball.
Carefully remove the moss and plastic. Try not to disturb the roots.
Plant the newly rooted tree in a pot and water the pot thoroughly.
Seal the upper part of the pot and the young plant against the elements by wrapping the pot and plant in polyethylene. Seal the sides and top with electrical tape, and run electrical tape around the base of the plastic to seal and secure it to the pot.
Poke two 1-inch holes in the plastic after about a week to begin to harden off the young tree to natural ambient moisture. Poke two more holes in the plastic every day for 5 days.
Remove the plastic tent and allow the plant to grow for several months in the pot before transplanting it outside or in a larger pot.