How to Plant Watermelon Seeds for the Best Results? A Detailed Guide to Sowing Methods
Watermelon, also known as summer melon, cold melon and so on, is an annual vining herbaceous plant of the genus Citrullus in the Cucurbitaceae family. Its original species may have come from Africa, and it has long been widely cultivated from the tropics to the temperate zones of the world. It is widely grown throughout our country, with a great many varieties, and the most famous ones come from **, Lanzhou in Gansu, Dezhou in Shandong, Liyang in Jiangsu and other places. Now let us take a look at how to plant watermelon seeds for the best results!
Seed Selection
Before sowing watermelon seeds, they should be carefully selected according to the characteristics of each variety, removing shriveled, insect-damaged, broken, moldy seeds and other debris. Then sun them for 1 to 2 noons, with a thickness of no more than 1 cm, turning them about once every 2 hours so they receive light evenly, in order to enhance seed vigor and improve germination energy and germination rate. A germination test should be done before sowing, and the sowing rate should be decided according to the seed germination rate. For direct sowing, generally 50 to 80 grams of seed are needed per mu.
Disinfection and Sterilization
1. Hot water seed soaking: Hot water seed soaking can prevent watermelon mosaic virus disease. 3 to 4 days before sowing, place the selected watermelon seeds in a clay pot and soak them in warm water of about 55°C made by mixing 2 parts boiling water with 1 part cold water. After the seeds are put into the warm water, stir constantly; when the water temperature drops to 30°C, stop stirring, keep them warm and soak for 3 to 5 hours, then wash off the mucus on the seed coat.
2. High-temperature scalding: High-temperature scalding can kill pathogenic bacteria on the seed surface. Put equal amounts of cold water and boiling water into two containers, with the water amount being 3 times the seed amount. First pour the selected seeds into the boiling water and stir quickly for 4 to 5 seconds, immediately pour in the cold water from the other container, and continue stirring until the water temperature drops to 30°C, then stop stirring and soak the seeds for 3 to 5 hours. Note that scalding must be done quickly, and the scalding time should not be too long, so as not to affect the seed germination rate.
3. Chemical disinfection: You can soak the seeds in 100 times diluted formalin for 30 minutes, or in a 2 to 4% bleaching powder solution for 30 to 60 minutes, or in a 500 times diluted 50% carbendazim solution for 1 hour, or in a 10% trisodium phosphate solution for 20 minutes, or in a 500 times diluted 50% amobam aqueous solution for 0.5 to 1 hour, or in a 500 times diluted 10% antibacterial agent 401 for 30 minutes.
Seed Soaking and Germination
1. Seed soaking: Seed soaking can speed up the water absorption rate of seeds and shorten the time for germination and emergence. The soaking time varies with water temperature, seed size, seed coat thickness and so on; when the water temperature is high and the seeds are small with thin seed coats, the soaking time should be shorter. Soaking in cold water for generally 6 to 10 hours is suitable, while soaking in warm water of about 25 to 30°C for 3 to 6 hours is enough. After soaking, rinse the seeds with clean water and rub them repeatedly to wash off the sticky material on the surface, so as to facilitate seed germination.
2. Germination: Germination ensures that after the seeds have absorbed enough water, the nutrients in the seeds are quickly decomposed and transported to supply the growth needs of the young embryo, so that under artificially controlled conditions the seeds can be promoted to germinate quickly. First rinse the soaked seeds with clean water, then wipe off the excess water attached to the seeds with a cloth. For a small amount of seeds, wrap them in a wet cloth and put them in a clay pot to germinate at 28 to 30°C; for a large amount of seeds, the cloth-roll method is suitable for germination.
Sowing Management
1. Seedbed preparation: For the watermelon seedbed, choose a plot that is sheltered from the wind, sunny, high and dry, and convenient to manage. For raising early-spring watermelon seedlings, it should be done in a greenhouse or plastic tunnel; to keep warm, electric heating wires can be laid to raise the soil temperature, and a small arch shed should be added over the seedbed. For raising watermelon seedlings for the late-autumn crop, a shade shed should be built, and attention should be paid to preventing erosion by heavy rain.
2. Soil preparation: The nutrient soil for the watermelon seedbed should be loose, free of pests and diseases, fertilized with nitrogen, phosphorus and potassium in proportion, and slightly sticky. You can evenly mix 6 parts paddy field topsoil, 3 parts decomposed barnyard manure and 1 part plant ash, and add 5 kg of decomposed chicken and duck manure per cubic meter of soil. Both soil and fertilizer should be crushed and sieved, kept granular, then thoroughly mixed with an appropriate amount of water, and piled for preparation 1 to 2 months before sowing.
3. Sowing at the right time: Early-maturing watermelons are sown from mid-December of the previous year to late March, mid-maturing watermelons are sown from April to June, and late-autumn watermelons are sown in mid-to-late July. On the afternoon of the day before sowing, water the nutrient pots thoroughly. When sowing, place the seed with the sprout tip flat in the nutrient pot, 1 seed per pot, cover with fine soil 1 cm thick, and cover with plastic film.
4. Seedling-stage management
① Temperature management: After the watermelon seeds are sown, the daytime temperature in the bed should be kept at 28 to 35°C and the nighttime temperature at 20 to 25°C. After 80% of the seeds break through the soil and emerge, keep it at 20 to 25°C during the day and 15 to 18°C at night. After the first true leaf appears, keep it at 25 to 28°C during the day. Start hardening the seedlings 1 week before transplanting.
② Water management: Generally, do not water again before the watermelon seedlings emerge. During the cotyledon stage, watering should be controlled, keeping the soil dry and wet alternately, with the main aim being to preserve soil moisture. After the true leaves unfold, the amount of watering can be increased. Water in the morning on sunny days, and after watering loosen the surface soil to preserve moisture; do not water on cloudy days, and also pay attention to uncovering the film for ventilation.