How to Grow Bitter Melon? A Detailed Guide to Key Bitter Melon Cultivation Techniques
Bitter melon is a short-day plant that likes warmth, loves light, tolerates heat and moisture, and does not tolerate shade. It is not strict about day length, and longer periods of light are beneficial to its good growth. It has relatively high requirements for soil moisture and air humidity, but does not tolerate waterlogging; it has wide adaptability and can be cultivated in many types of soil across northern and southern China. In recent years, some...
Bitter melon is a short-day plant that likes warmth, loves light, tolerates heat and moisture, and does not tolerate shade. It is not strict about day length, and longer periods of light are beneficial to its good growth. It has relatively high requirements for soil moisture and air humidity, but does not tolerate waterlogging; it has wide adaptability and can be cultivated in many types of soil across northern and southern China. In recent years, some vegetable growers in certain areas have also grown it in polytunnels or greenhouses.
1. Choosing a good variety is the key to a high yield. Large White Bitter Melon and Green Bitter Melon 915, bred by the Institute of Vegetables and Flowers of the Chinese Academy of Agricultural Sciences, are favored by vegetable growers for their many advantages, such as good quality, high yield and strong disease resistance. Before sowing, first scald the seeds with hot water at 55°C and stir; when the temperature drops to 30°C, soak the seeds for 12 hours (if you gently crack open a small slit in the seeds, it helps them absorb water, and the soaking time is 8 hours). Then wash the seeds, take them out, wrap them well in clean gauze, and place them in an incubator at about 30°C to sprout. Wash them once a day with warm water, and they will begin to sprout in about 4-5 days. In this way, you can both kill the pathogens carried by the seeds and ensure uniform sprouting.
2. Sowing For open-field cultivation of bitter melon, seedlings are generally first raised in a solar greenhouse. The day before sowing, put the prepared nutrient soil (take garden soil that has never grown cucurbits, grass peat: vermiculite: decomposed dry human manure = 1:1:1:0.5; add 1 kg of diammonium phosphate per cubic meter, sieve and mix evenly, then pile it up, cover it tightly with plastic sheeting, and it can be used after a few days; when using it, mix it evenly once more) into 10 cm x 10 cm nutrient pots, or put it into a prepared seedling bed (use wooden strips to mark the bed into 10 cm x 10 cm squares, and make 1 cm deep holes in the middle of the squares with a wooden stick), and water thoroughly. The next day, spray the nutrient soil with water again, then scatter a thin layer of sieved fine soil and sow. Place the sprouted seeds in the small holes (note: with the sprout facing downward against the soil), cover the seeds with a small mound of soil about 1.5 cm thick, and then scatter a layer of fine soil all over. Taking the Beijing area as an example, sowing is generally done at the end of March or the beginning of April, the seedling age is about 30-35 days, and they are planted in the open field after the final frost in early May. Raising strong seedlings is one of the key elements in producing pollution-free vegetables.
3. Seedling management After sowing, keep the greenhouse sealed to raise the temperature. Set up small arched tunnels in the sowing bed and cover them with film to raise the temperature and retain moisture, keeping the daytime temperature at 30-35°C and the nighttime temperature above 15°C. When 50% of the seedlings have emerged, promptly cover the film of the small arched tunnels again. After the seedlings have all emerged, keep the indoor temperature at 20-25°C during the day and around 10°C at night. Water whenever the soil looks dry, following the principle of controlling temperature but not controlling water, so as to keep the seedlings growing vigorously. After that, gradually lower the temperature in the tunnel, and remove all the tunnel film a few days before planting out to harden the seedlings.
4. Planting out Because bitter melon is a warmth-loving, fertilizer-tolerant crop, sufficient base fertilizer is needed. Apply 5,000 kg of high-quality organic fertilizer and 30 kg of diammonium phosphate per 667 sq m, mix evenly, first make a flat bed at 1.5 m and water it, and after a few days when the soil is slightly dry and loose, make small raised beds with a bed surface width of 80-90 cm and a height of 10-15 cm. Lay plastic mulch 5-7 days before planting out. Two rows per bed, with a plant spacing of 60 cm, and plant out along a marked line. Do not dig the holes too deep; it is best if they can hold a little water after planting out. To prevent the soil temperature from dropping, the squat-water planting method is generally used. After the water in the holes has seeped away, seal and press the holes firmly with soil to prevent air leaks. After planting out, set up the trellis promptly. Because bitter melon grows very vigorously, a sturdy A-frame trellis should be set up. The spacing between trellis frames is 20 cm (30 cm for slightly thicker trellis material). Setting up the trellis promptly can also improve the field microclimate and help the seedlings recover quickly. Plant 1,300-1,600 plants per 667 sq m, using 250-300 g of seed.
5. Field management After the seedlings have recovered, water promptly with recovery water, but since the temperature is still low at this time, the amount of water should not be too large. After a few days, carry out deep intertillage promptly to preserve soil moisture, raise the soil temperature and promote plant growth and development. Because the plants branch strongly, select 2-3 thick vines from the lower part, tie them to the trellis, and remove all the rest. During this period, generally do not water. When the first melon has fully set and begins to swell, water and apply 10-15 kg of urea or 20-25 kg of ammonium bicarbonate per 667 sq m with the water. Because the plants have now entered the vigorous growth stage, watering and fertilizing should be based on weather changes, plant growth conditions and soil conditions. This is what is meant by watering according to "the sky, the soil and the crop." It should be noted that because bitter melon has a relatively developed root system and strong plant vigor, do not water too frequently or too heavily, so as to avoid growing only vines without setting fruit, or poor ventilation and light transmission causing disease, or knocking down the trellis and causing economic loss. About 40-50 days after planting out, harvesting of the marketable melons begins. The fruiting period requires relatively large amounts of fertilizer and water.
6. Pest and disease control Because bitter melon has strong disease resistance and few diseases, leaf mold, powdery mildew and the like generally occur in the late growth stage. Generally, spray with 50% thiophanate-methyl wettable powder at 1000 times or 10% triadimefon emulsifiable concentrate at 1500 times. Spray with 20% omethoate at 1000 times to control aphids, and spray with propargite at 1500-2000 times to control red spider mites and tea mites.