How to raise bitter melon seedlings so they come up uniform and strong?
The seed coat of bitter melon is thick and hard. If the seeds are sown directly into the field, water does not easily penetrate inside, germination is slow, the seedlings emerge unevenly, and the rate of missing plants is relatively high. Therefore, the seeds should be soaked and pre-germinated before sowing. (1) Pre-germination method: first put the seeds into warm water at about 55°C and soak them for 10 minutes to sterilize...
The seed coat of bitter melon is thick and hard. If the seeds are sown directly into the field, water does not easily penetrate inside, germination is slow, the seedlings emerge unevenly, and the rate of missing plants is relatively high. Therefore, the seeds should be soaked and pre-germinated before sowing.
(1) Pre-germination method: first put the seeds into warm water at about 55°C and soak them for 10 minutes to sterilize and disinfect. Then soak them in clean water at room temperature for 4-5 hours, so that the bitter melon seeds absorb enough water and are stimulated to sprout and germinate. Then scoop out the seeds, wash off the gelatinous substance on the seed coat, let them dry slightly, and wrap them in clean, moist coarse cotton cloth and place them in a constant-temperature cabinet at 28-33°C for pre-germination. If there is no constant-temperature cabinet, the bitter melon seeds can be placed in a clay jar or iron bucket with a 40-60 watt electric light hung above, heated day and night, and the mouth of the jar should be covered to maintain a constant-temperature environment. Place a thermometer in the clay jar or iron bucket so that the temperature stays at 28-33°C. During pre-germination, check morning and evening every day. If the temperature in the jar is low, add bulbs; if the temperature is too high, switch to lower-wattage bulbs (if conditions permit, a temperature controller can be used for better results). When the seeds are dry, spray water to keep them moist. After soaking and heated pre-germination, bitter melon seeds begin to sprout after 30 hours and can sprout completely in 2-3 days. During pre-germination, check frequently every day, pick out the seeds that have already sprouted, and sow them. If mold has grown on the surface of seeds that have not sprouted, wash them promptly with clean water and then continue pre-germination until sprouting is complete.
(2) Plastic film greenhouse. A greenhouse that uses plastic film as the transparent roof is called a plastic film greenhouse. Plastic film greenhouses can obtain a relatively complete spectrum, and their effect on promoting seedling growth is better than that of glass greenhouses. Plastic film greenhouses are easy to build, come in diverse configurations, and are low in cost. At present, in southern China, galvanized pipe arched sheds, 6 m steel-bar arched sheds, or bamboo-and-wood arched sheds are mostly used.
(3) Other seedling-raising equipment. In southern China, shade-based seedling raising is commonly used in the hot summer. At present, shade nets are used more often. Shade nets, also called cooling yarn or cold yarn, are a new type of lightweight, high-strength, aging-resistant, net-like agricultural covering material made mainly from polyolefin resin by drawing and weaving. The width of the net is 900 mm, 1500 mm, 1600 mm, 2000 mm and 2200 mm; the colors include black, silver-gray, white, etc.; and the shading rate is 20-75%. The shading and cooling effect of shade nets: if covered in midsummer, the surface temperature can generally be reduced by 4-6°C, and the soil temperature at 5 cm underground is 3-5°C lower than in the open field. Using black shade nets can reduce the temperature by up to 9°C. After shading, wind speed is reduced, humidity is increased, and soil evaporation is reduced, so it also has the effect of preserving soil moisture and preventing drought. In addition, its effect in preventing heavy rain is also very good.
Preparation of seedling nutrient soil
Nutrient soil is the foundation that supplies the water, nutrients and air needed for the growth and development of bitter melon seedlings. The quality of seedling growth and development is very closely related to the quality of the bed soil. Good bed soil should be fertile, warm, loose and fine. It is generally required to have an organic matter content of 15%-20%, a total nitrogen content greater than 0.5%, an available nitrogen content greater than 6×10-5, an available phosphorus content greater than 10×10-5, an available potassium content greater than 10×10-6, and a pH of about 6.5. Usually, taking 2/3 garden soil and adding 1/3 decomposed pig, cattle and chicken manure can meet the above requirements.
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