Bitter Melon Open-Field Cultivation Techniques: Sow at the End of March, Tie Vines to the Trellis Later

AbstractSeed selection and sprouting: Select a high-quality variety, soak the seeds, then place them in a 30°C insulation box to sprout. Raising seedlings and sowing: After raising seedlings in a greenhouse, sow at the end of March. Seedling stage management: Control the temperature inside the arched shed well, keeping it between 28-35°C during the day and above 15°C at night. Planting bitter melon: Apply a sufficient amount of base fertilizer, make flat beds, then water. Field management: In the later stage, tie the vines to the trellis.

1. Seed Selection and Sprouting

To grow bitter melon, choose a variety with good quality, high yield and strong disease resistance, then blanch the seeds in hot water at about 55°C while stirring, and when the temperature drops to about 3°C, soak the seeds for another 12 hours. You can crack a small slit in the seeds so they can absorb water better, then soak them for about another 8 hours.

Wash the soaked seeds clean, take them out, wrap them in clean gauze, and place them in an insulation box at about 30°C to sprout. During this period, wash them once a day with warm water, and they will begin to sprout in about 5 days.

2. Raising Seedlings and Sowing

For open-field cultivation, first raise seedlings in a greenhouse. You can use field soil that has not grown cucurbits or fruits for seedling raising. Mix dry human manure and new peat at a 1:1 ratio, then add 1000 grams of diammonium phosphate per cubic meter, filter and mix evenly to make nutrient soil. One day before sowing, put the nutrient soil into seedling beds 10 cm long and wide, then water thoroughly.

On the second day, spray the nutrient soil once more with water, then cover the seeds with a small mound of soil about 1.5 cm high, and sprinkle a layer of filtered fine soil. Sowing is generally at the end of March or early April, the seedling age is about 28-35 days, and after there is no frost in early May, they can be planted in the open field.

3. Seedling Stage Management

After sowing, control the temperature inside the small arched shed well. Generally, keep the daytime temperature between 28-35°C, and the nighttime temperature above 15°C. After the emergence rate reaches 50%, promptly remove the covering film of the small arched shed, then cover with about 0.5 cm of filtered fine soil to fill the cracks, which can better maintain the moisture in the soil.

At noon, provide ventilation and appropriate cooling, and at night cover the shed film well. After the bitter melon seedlings have all emerged, keep the daytime temperature at about 18-25°C and the nighttime temperature at about 10°C. During this period, water whenever the soil is slightly dry, which is beneficial for the healthy growth of the seedlings. Later, the temperature inside the shed can be gradually lowered. A few days before planting, remove the covering film in the shed to improve the resistance of the seedlings.

4. Fertilizing and Building the Trellis

Bitter melon is a crop that is relatively tolerant of fertilizer. When planting, apply a sufficient amount of base fertilizer, about 5000 kg of high-quality organic fertilizer per mu plus 30 kg of diammonium phosphate. Make flat beds, then water, and after the soil is slightly dry and loose, make small raised beds with a width of 80-90 cm and a height of 10-15 cm, and lay plastic film 5-7 days before planting.

Generally, there are two rows per bed, with a spacing of about 60 cm between each plant. Planting should also be done along marked lines. Do not dig the holes too deep. Bitter melon grows relatively fast, so after planting, promptly build a trellis, with a seed rate of about 250-300 grams, and about 1300-1600 plants planted per mu.

5. Field Management

After planting, water regularly to help the seedlings recover. The branching ability of bitter melon plants is strong. Generally, select 2-4 thick vines from the base, then tie the vines to the trellis, and remove the excess ones. At this time, there is no need to water the bitter melon anymore, but when the first melon gradually grows larger, you can add 10-15 kg of urea or about 20-25 kg of ammonium bicarbonate to the water when watering.