Bitter melon plants are related to melons and gourds. This semi-tropical vine requires a long, hot growing season to produce fruits. In areas outside the tropical and sub-tropical climate ranges, bitter melon seeds should be started indoors to get a head start on the growing season. When planting bitter melon seeds, one of the best tips is to use biodegradable pots to minimize root disturbance. Melon seeds require warmth and moisture to germinate successfully.
The best time to start planting bitter melon seeds is two to four weeks before the last frost date. Bitter melon seedlings can be planted outside into the garden bed as soon as all danger of frost has passed. By starting the seeds indoors, the young seedlings will be ready to plant out right at the beginning of the growing season.
Melon and gourd plants, including the bitter melon, do not tolerate root disturbance well. The best pots to use with bitter melon seeds are peat pots. Peat pots are made from compressed, biodegradable peat-based materials and are designed to break down quickly in the soil. The whole pot can be plated out at transplant time. With soil microbes, worms, water and the developing plant root system, the peat pot disintegrates, leaving the roots free to grow into the surrounding soil.
Temperature is important when planting bitter melon seeds. The seeds germinate best in a temperature range of 70 to 90°F (about 21 to 32°C). At 60°F (about 15°C), germination time increases. The seeds commonly take between three and 12 days to germinate.
One of the best tips when planting bitter melon seeds is to use a sterile soil-less potting medium; peat moss or coconut coir are common seed starting mediums. Coconut coir is made from shredded coconut husks. It serves a similar purpose in horticultural use and is considered a more sustainable product than peat moss. The peat or coir can be blended with vermiculite or perlite to create a light soil mix with good drainage.
When the plants develop two sets of true leaves, the bitter melon seedlings can be transplanted out into the garden. The first leaves to emerge are called seed leaves. The seed leaves are followed by true leaves.
Bitter melon plants are climbing vines that require a structure to scale. As such, the seedlings should be planted at the base of a trellis. The plants grow best with six or more hours of sun per day.