The mangosteen is a sweet, tropical fruit that grows on trees that can reach 80 feet tall in the wild. Purdue University classifies mangosteen as an ultratropical plant, meaning it cannot withstand temperatures below 4.44 degrees Celsius or above 37.8 degrees Celsius. For this reason, the tree has not adapted well to planting in many parts of the world. You can grow a tree in a container as long as you can provide for the mangosteen's climate and other needs.
Fill a large planting pot two-thirds full with well-draining, organic soil. At its smallest, this tree grows above 15 feet, so you will need an extremely large pot with drainage holes for this plant. Use only organic, well-draining soil and specify these needs at the garden centre or nursery where you purchase the soil. The mangosteen will not thrive in other soil.
Soak your mangosteen seed in water for 24 hours before planting to increase the chance of germination, recommends the Purdue University Extension Service. Water the soil in your pot so water runs out the drainage hole. Insert the mangosteen seed into the soil and cover the seed with about 1 inch of soil.
Place the container in an area of your home that remains constantly above 7.22 degrees Celsius and below 37.8 degrees Celsius. The area should have a high humidity (constantly above 65 per cent). The plant should receive six to eight hours of daily indirect sunlight or light from a grow light.
Water the mangosteen constantly. In the wild, the tree grows best in areas that receive between 60 and 80 inches of water per year, which means it needs at least 1½ inches of water per week. Water any time the top inch of soil feels dry to the touch.
After planting, the seed should begin to sprout within three weeks. It can take more than two years to reach 1 foot high and 10 to 20 years to produce fruit, reports the Purdue University Extension Service.
Seeds lose their viability within five days of removal from the mangosteen plant. Use only fresh, plump seeds or you may not get any plants at all.