You can easily grow orange trees in containers indoors, especially if you have plenty of room for the trees. You can also select a dwarf variety, such as the Dwarf Venous Orange Fruit Tree, which is a more ideal size to grow indoors. Select a container for your orange tree that is large enough to accommodate the tree as it grows. You can begin with a container that is about two or three times the size of the nursery container. Ensure that the planting container has at least three large drainage holes in the bottom.
Cut a piece of fine mesh to fit inside the bottom of the planting container. Lay the mesh over the drainage holes in the bottom of the container.
Spread 1 to 2 inches of gravel into the bottom of the container on top of the mesh. Fill the bottom one-third of the container with all-purpose potting soil.
Remove the orange tree carefully from the nursery container. Place the tree's root ball into the center of the planting container.
Fill in the rest of the container around the tree's roots with the potting soil. Fill the potting soil just up to the same level as the nursery container.
Water the tree to moisten the potting soil until the water begins to drain from the bottom of the container. Place your orange tree next to a sunny window where it will receive bright sunlight.
Water your orange tree once or twice each week, when the top 1 inch of potting soil feels dry to the touch.
Feed your orange tree once each year in early spring with a slow-release citrus tree fertilizer. Follow the dosage instructions on the label carefully and don't apply the first dose of fertilizer until new growth emerges on the newly potted orange tree.