Bitter melon, or momordica chanrantia, is part of the gourd family and is grown primarily in China, India and throughout Southeast Asia. In the United States, bitter melon is grown mostly in California and Florida, due to the warmer climates. Bitter melon is grown for its immature fruits, which are mostly used in Asian cooking, and contain vitamin C, vitamin A, iron and thiamin. The fruits are indeed bitter and only increase in bitterness as the fruit matures. Bitter melon takes some work to grow and cultivate, but growing these plants is similar to growing other climbing and trailing gourds, such as watermelon and cucumber. If you live in a warm climate, you can grow bitter melon outdoors successfully.
Soak your bitter melon seeds in water in a small dish for 48 hours. Plant your seeds in full sun in the spring. Wait to plant the seeds outdoors until the nights are consistently 50 degrees Fahrenheit or warmer.
Prepare your soil. The soil should be well-drained and ideally sandy loam, silt loam or another type of light sandy soil. Consider tilling sand into the ground before planting the seedlings if your soil is heavy clay or dense. Till in or broadcast a mixture of phosphorous and nitrogen fertilizer prior to planting. Try a 24-8-0 or 12-4-4 fertilizer, making sure that the nitrogen count (the first number) is three times greater than the phosphorous count (the second number).
Plant your bitter melon seeds one-half inch deep in the soil. Space the seedlings 18 to 24 inches apart.
Erect a trellis next to the seedlings. Make a trellis that is approximately 6 feet high with wooden stakes spaced 4 to 6 feet apart. Run a wire along the bottom of the stakes and one along the top. Tie strings to the wires, running them vertically in between the stakes.
Water your bitter melon plants daily. Distribute enough water to your plants so that the top 18 inches of the soil stays moist. Use a nitrogen and phosphorous liquid fertilizer once a week in your water.
Harvest the bitter melon fruits while they are firm and light green, approximately 8 to 10 days after the flower opens. If you allow the fruits to mature, they will become spongy and more bitter, and this will also prevent new fruits from growing.