Remove all of the flesh from the mango pit by scraping it off with a nylon scrubbing pad. Set the seed on a paper towel and allow it to dry for two days.
Slide a chisel or knife between the two halves of the mango pit and pry it open to reveal the seed inside. It looks like a large lima bean; the lighter colored area on one end is called the "eye."
Hold the mango seed vertically with the "eye" pointing upwards. Push one toothpick about 1/8 inch into one side of the seed and another toothpick into the opposite side. Set the ends of the toothpicks on the edges of the 1-pint jar. Fill the jar with lukewarm water to cover the lower half of the seed.
Check the water levels in the jar daily. If the water line is below the lower half of the mango seed, add more water. Watch for signs of germination. Sprouting usually begins within two weeks of soaking. Remove the mango plant from the water once green sprouts and white roots have developed.
Fill a 10-gallon pot with organic potting soil. Plant the seed approximately 2 inches below the soil level with the roots pointing downward. Keep the soil moist at all times as the mango plant grows. Set the plant in a warm area that receives bright sunlight.