The planting time of bitter melon is generally March. Some seedlings are first raised in a greenhouse or greenhouse and then transplanted. They can be sown in February in advance.

Sowing and Propagation

Germination

Field management selects varieties such as large white balsam pear and green balsam pear with good quality, high yield and strong disease resistance. Scald the seeds with 55℃ hot water, stir, and soak the seeds for 12 hours when the temperature drops to 30℃. If the seeds are lightly cracked to open a slit, it will help the seeds absorb water. Soak the seeds for 8 hours. Then wash the seeds, take them out, wrap them in clean gauze, and put them in an incubator at about 30°C for germination. Wash them with warm water every day and they will start to sprout in 4 to 5 days.

Sowing seeds

For open field cultivation, seedlings can be grown in a greenhouse first. Take field soil that has not been planted with melons, peat, vermiculite and dried human feces, mix them in a ratio of 1:1:1:0.5, add 1000 grams of diammonium phosphate per cubic meter, sift and mix evenly to form a nutritious soil. The day before sowing, put the nutrient soil into a 10 cm × 10 cm nutrient bowl (or seedling bed) and water it thoroughly. The next day, spray the nutrient soil with water again, sprinkle a thin layer of sieved fine soil and sow. Cover the seeds with a small mound of soil about 1.5 cm thick. Then spread a layer of fine soil all over. In Beijing, sowing is usually done at the end of March or early April, and the seedlings are 30 to 35 days old. Plant in the open field after the last frost in early May.

Seedling stage

Seal the greenhouse after sowing. A small shed is inserted into the border and covered with film to keep the temperature at 30-35℃ during the day and above 15℃ at night. After 50 days of seedling emergence, remove the small shed film in time and cover it with 0.5 cm of sieved fine soil to bridge the cracks and maintain the humidity in the soil. Let the air cool down at noon, and then cover the shed with film at night. After the seedlings emerge, the temperature should be kept at 20-25°C during the day and around 10°C at night. Water when dry, control temperature but not water to maintain healthy growth of seedlings. Then gradually lower the temperature in the shed, and a few days before planting, all the shed films will be lifted to harden the seedlings.

Planting

Bitter melon is a temperature-loving and fertilizer-tolerant crop and requires sufficient base fertilizer. Apply 5,000 kilograms of high-quality organic fertilizer and 30 kilograms of diammonium phosphate per acre. First make a flat border and water it. After the soil is slightly dry and loose, make a small sorghum border with a width of 80 to 90 cm and a height of 10 to 15 cm. Apply mulch 5 to 7 days before planting. There are two rows in each border, with a spacing of 60 cm between plants, and line planting. The hole should not be dug too deep so that it can be slightly blocked after planting. Because bitter melon grows very strongly, a herringbone trellis must be inserted promptly after planting. Plant 1,300 to 1,600 plants per acre, and use 250 to 300 grams of seed.

Cultivation management

Field management

After slowing down the seedlings, pour water to slow down the seedlings in a timely manner, and deep tillage after a few days. Since the plant has strong branching ability, select 2 to 3 thick vines from the lower part, tie them up and put them on the shelf, and knock off the rest. During this period, watering is generally no longer required. When the first melon has all sat down and begun to expand, water it and follow the water with 10 to 15 kg of urea or 20 to 25 kg of ammonium bicarbonate.

Shed management

Uncovering the thatch and ventilating

Uncovering or releasing the thatch every morning and evening until mid-May of the following year. In rainy and snowy weather in winter, it is necessary to cover the grass thatch with a rainproof film in time to prevent the grass thatch from getting wet, and at the same time, it can also increase the shed temperature by 2-3°C. When the temperature of the shed exceeds 32°C, the film should be removed in time to let the air cool down. At 20℃, close the vents to control the shed temperature between 25-30℃.

Pruning

When the vines begin to grow, use thin nylon ropes to lift the melon vines so that they grow upward. Bitter melon generally does not need to be pruned, but thin side branches at the base and overly dense and aging yellow leaves should be appropriately pruned to facilitate ventilation and light transmission.

Pollination

After the bitter melon blooms, artificial pollination must be carried out every day. The method is: take the male flowers that bloom that day, remove the petals, and lightly apply the pollen from the stamens to the stigma of the pistil. The optimal pollination time is 9 o'clock in the morning. When pollinating, pull the young melons down to the bottom of the melon vines so that the melons hang downward and grow long without bending and have a beautiful appearance.

Fertilization

Bitter melon is intolerant to fertilizer during the seedling stage, so less fertilizer should be applied more frequently. Generally, it is mainly decomposed chicken manure and nitrogen fertilizer. Generally, there is no need to fertilize before the end of the year, just watering. Water once every 20 days in winter, and water lightly to avoid excessive humidity, which may aggravate diseases and cause root retting.

After the melons are set, sufficient fertilizer and plenty of water should be applied. Apply 7-10 kilograms of urea or compound fertilizer per mu each time watering, plus about 100 kilograms of decomposed chicken manure.