Propagating lemon trees is a fairly simple process. Grafting buds from an established lemon tree onto a rootstock is a reliable way to propagate a lemon tree. Growing lemon trees from seed is unreliable. To get the same lemon tree as the one you are propagating, it is necessary to graft a section of the old tree onto new rootstock. Growing lemons is fun and rewarding, but if you live in cold, northern climates your lemon tree will have to live indoors during the winter.
Select a budding branch about the thickness of a pencil from the tree you wish to propagate.
Cut a small budding branch from an established lemon tree with a sharp knife. Cut the shoot to be 8 to 10 inches long with several green, healthy looking buds along its length.
Remove any leaves from the budding section of the branch; this branch is called the bud wood.
Select the rootstock to be used to propagate your lemon tree, choosing rootstalk from a citrus tree that is known for vigorous, hardy growth.
Select an area on the rootstock about 6 inches from the ground and remove all thorns, leaves and branches.
Make a perpendicular cut in the bark of the rootstock about 1 to 1-½ inches long. At the bottom of the perpendicular cut make a horizontal cut about 1 inch long. This will produce an upside-down, T-shape cut.
Cut a bud from your bud wood by sliding a very sharp knife under the bark and removing 1 inch of bark with a single bud on it.
Pull back the bark in the cut area of the rootstock and insert the section of bark and bud into the cut.
Fold the rootstock bark over the bark surrounding the bud, but leave the bud exposed.
Wrap the bud with budding tape by starting at the bottom and working the wraps up to the area just above the bud. The tape should be secure but not tight.
Remove the budding tape after 20 days.
Fell the rootstock tree just above the new budding growth when the newly-budded shoot has grown to 1 to 2 feet.