Though most gardener's objective is not to grow the largest trees, if you want to get the the largest trees possible that are capable of producing the most oranges, there are a number of steps you can take. Utilizing these tips should not sacrifice the quality, and may enhance both the quality and size of the fruit. To grow oranges effectively, keep in mind that the trees need nutrients, water and sunshine more than anything else.
One of the most important things you can do to encourage orange tree growth is make sure you provide enough light for your tree. Light helps the tree produce the energy that is needed to power fruit production. In order to make sure the tree is getting enough light, plant it in full sun. If you plant the tree on a hill, make sure the tree is on a south-facing slope. Further, remember that pruning can ensure that enough light reaches the entire tree, but also that pruning can result in energy being transferred to fewer locations. If you do prune, do so sparingly.
Producing sweet, juicy fruit can take a great deal of nutrients out of the soil. Therefore, if you want the fruit tree to grow larger, the best option is to use a fertilizer heavy in nitrogen, perhaps with an N-P-K ratio of 2-1-1 or 3-1-1. If the fertilizer is slightly acidic, that would also be beneficial as citrus trees, including oranges, generally prefer to have a slightly acidic soil. Fertilization should be done every month during the active growing season and one or twice during more dormant periods. If you want more specialized direction on which fertilizer to use, take a soil sample in for testing to your local extension office.
Citrus trees are often capable of withstanding some moderate drought conditions, especially in more dormant times of the year. However, the ideal conditions for optimum growth include regular watering in a soil that is well drained. You should not water orange trees too much or keep the soil saturated because too much moisture can promote root rot. Water when the soil becomes dry to the touch.
If the size of the orange tree is a priority, your best choice may be the navel orange. This tree is one of the tallest growing, capable of reaching heights of up to 30 feet and growing out as far as 20 feet in diameter. The Washington navel orange is one of the most juicy and popular of all orange trees as well and can easily be grown in a grove or a backyard.