Keep the bitter melons in a warm, humid spot that gets full sun. The plant grows poorly in cool temperatures. If you plant when the nights are still under 50 degrees F, cover the plants with the top half of a cut plastic bottle for warmth.
Install a trellis next to the plant once it germinates. Bitter melon is a vining plant, and giving it a trellis to climb will keep it from taking over your garden space. It also prevents the fruits from becoming misshapen.
Water frequently enough to keep the soil moist to the touch. Lay a 2 inch layer of straw mulch to keep down weeds and maintain soil moisture levels.
Apply 1 ounce of urea-based fertilizer to the soil around the base of the plant every two weeks, once fruit begins to develop. Pick the fruits when they are still immature and have a light green color.