Orange trees are fairly simple to grow from a seed. However, if you do not know how to care for your tree as it passes through different growth stages, you may kill your plant with the best of intentions. Understanding what stage of growth your orange tree is presently in will help your tree reach a healthy maturity. Also, you will be better able to determine when to expect flowers and fruit from your orange tree.
Reproduction and Early Growth
Orange trees grow from both seeds and cuttings. Either way, the first year of growth is critical to your tree's future hardiness. Make sure you water the orange tree regularly and feed it a water-soluble fertilizer. During this time, the seeds will sprout and may grow anywhere from 1 to 4 feet. The tree will still clearly be young and slim, however, and can remain in a pot at this time. Keeping your tree potted for the first year is a good tactic because it will enable you to bring the tree in if the temperature takes a sudden drop. Older trees can withstand this, but younger trees will die.
Sapling and Pole Stages
Once your orange tree has reached its first "birthday," it will likely be between 2 and 5 feet high. Tie it to a pole for support, as it may grow taller than it can support on its own. This is why the sapling stage is also called the pole stage. During this time, your tree will develop more branches and a sturdier shape. This period will last for the next two to five years, depending on the type of orange tree you have and the growing conditions. Plant the trees in the ground outside if you live in a warm climate, or keep them in large pots if temperatures drop below 20 degrees F during your local winters. If you move these trees indoors for cold weather, you can accelerate their fruit development. Trees flower and produce fruit toward the end of the sapling and pole stages.
Orange trees are mature when they start to bear flowers and fruit. Reaching this stage can take as long as 10 years for some species, but will occur much sooner (around three or four years) for others. If your orange trees live outside year round and are exposed to cold temperatures, they may flower but not bear fruit, or only develop lush foliage as they mature. You will be able to tell from their hardiness (cold around freezing temperatures will no longer kill them) and their shape---they will be sturdier and have a round or ovoid branch structure---that they are now fully mature.