Grapefruit plants are very attractive trees, with shiny green leaves, fragrant white flowers and, of course, grapefruits. Grown outdoors, grapefruit trees prefer warmer, more humid climates, growing best in subtropical conditions, usually in zones 9 or 10. However, the plant can be grown indoors as ornamentals and can even flower and bear fruit, given the right amount of light and moisture. Most grapefruits have several seeds which you can germinate at home to raise your own grapefruit plant.
Cut open a grapefruit and remove the seeds.
Prepare a planting medium by mixing equal amounts of potting soil and sand. Cut the drinking cups down to about three inches tall and punch holes in the bottom for drainage. Fill the cups with the planting medium.
Plant the grapefruit seeds, while they are still fresh and moist. Insert one seed approximately half-inch deep in each cup. Cover the seeds with potting medium and water lightly.
Place the each cup in a zip-top plastic bag and seal the bag. Put the cups in a warm place to encourage them to germinate. Keep the soil damp but not wet.
Check the grapefruit seeds after about a week or two for signs of growth. Once the seeds have sprouted, remove the plastic bag. After the seedlings have three to four leaves on them, transplant each seedling to a one gallon pot.
Ensure that the juvenile trees receive about four hours of direct sunlight each day and temperatures remain between 60 and 70 degrees F.
Replant each grapefruit tree in a larger pot each spring to help promote fruiting.
Check your hardiness zone to see if a grapefruit tree will grow outdoors in your area. Plant your tree outdoors by digging a hole twice as deep and wide as the root ball of the tree. Place the tree in the hole and back fill the hole, being careful not to cover the trunk with soil.
Prune your trees, as they mature, in early spring to encourage new growth. Water regularly, keeping the soil damp, but not wet. Feed twice a year with a good citrus fertilizer.