Want high-yielding watermelons? You need to master these growing techniques
In the scorching summer, the first fruit everyone definitely thinks of is watermelon, because watermelon is sweet and delicious, clears heat and relieves summer heat, and is the best-selling fruit in summer. So how do you grow watermelon? How can you grow watermelon to increase yield? Below, the editor introduces the high-yield cultivation of watermelon.
High-yield watermelon cultivation techniques
1. Seed soaking and sprouting: Before sowing, sun-dry the seeds for 2 days, then disinfect the seeds. Soak the seeds in 55°C warm water, stirring while soaking for about 30 minutes, then continue soaking for 2 hours after cooling. For chemical treatment, usually use 100 times formalin solution to soak the seeds for 30 minutes, or use 50% carbendazim 500 times solution to soak for 1 hour, rinse clean with clear water, then soak for 3-4 hours. Wash the treated seeds clean, place them in a constant-temperature chamber at 40°C for 6 hours of high-temperature activation, then sprout them at a constant 33°C. When the radicle grows to 0.5 cm, they are ready for sowing.
2. Preparing the seedbed: Choose a plot that is sheltered from the wind, faces the sun, has high and dry terrain, and is convenient to manage to build the seedbed. For early-spring watermelon seedling raising, it should be done in a greenhouse or plastic tunnel, where electric heating wires can be laid to raise soil temperature, and a small arched frame can be added over the seedbed. For late-autumn watermelon seedling raising, a shade shed should be built, and protection against heavy rain erosion is needed. The nutrient soil should be loose, free of pests and diseases, and fertilized with nitrogen, phosphorus, and potassium in proportion, slightly sticky. You can use 6 parts paddy field topsoil, 3 parts decomposed barnyard manure, plus 1 part plant ash, mixed evenly, 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 mixed thoroughly with an appropriate amount of water, and piled for 1-2 months before sowing. Use nutrient pots for seedling raising, with a pot mouth diameter of 6-8 cm, made from waste newspaper, with each large newspaper making 10 paper pots; plastic pots or clay pots can also be used. Put the nutrient soil into the nutrient pots, 1-2 cm below the pot mouth, and arrange them neatly in the seedbed.
3. Sowing: Early-maturing watermelon is sown from mid-December of the previous year to late March, mid-maturing watermelon is sown from April to June, and late-autumn watermelon is sown in mid-to-late July. On the afternoon of 1 day before sowing, water the nutrient pots thoroughly. When sowing, place the seeds with sprouted tips flat in the nutrient pots, 1 seed per pot, cover with fine soil 1 cm thick, and cover with plastic film.
4. Seedling stage management: ① Temperature management: After sowing, the daytime temperature in the bed should be controlled at 28-35°C and nighttime at 20-25°C; after 80% of seeds break through the soil and emerge, keep it at 20-25°C during the day and 15-18°C at night; after the first true leaf appears, keep it at 25-28°C during the day. Start hardening the seedlings 1 week before transplanting. ② Water management: Generally no more watering before emergence; during the cotyledon stage, watering should be controlled, keeping the surface dry and wet alternately, mainly to preserve soil moisture; after true leaves unfold, watering can be increased. Water in the morning on sunny days, loosen the surface soil after watering to preserve moisture, and do not water on cloudy days. In addition, pay attention to uncovering the film for ventilation to prevent high temperature and high humidity. During the seedling stage of late-autumn watermelon, high temperature and dryness occur, so attention should be paid to water supply.
Temperature management
1. Planting—vine spreading stage: That is, the period from planting until the watermelon seedlings with 5-6 leaves turn from upright growth to creeping growth, about 13-15 days. In the first three days after planting, generally do not ventilate, to promote seedling recovery. After seedling recovery, gradually increase ventilation from 10 a.m. to 2 p.m. every day, to achieve cooling, moisture removal, improved light conditions, reduced plant growth speed, and enhanced stress resistance, achieving thick leaves, thick stems, and strong roots.
2. Vine spreading stage—fruit setting: This stage has already entered late April, the late frost period has passed, and generally there is no need to consider frost damage. In this period, the plant roots, stems, and leaves grow rapidly, and it is very easy for excessive vegetative growth to cause difficulty in fruit setting. Therefore, it is necessary to increase ventilation in the morning and at noon, and cover with film loosely at night to promote reasonable nutrient distribution and earlier fruit setting.
Grafting techniques
Approach grafting of pumpkin and watermelon: When the pumpkin cotyledons are flat and the growing point is exposed, remove the growing point, and at 0.5-1 cm below the cotyledons use a blade to make a downward diagonal cut at a 45-degree angle, with a depth of 2/5-1/2 of the stem thickness, and a cut length of about 1 cm. At the same time, on the corresponding part of the watermelon scion, make an upward diagonal cut at a 45-degree angle, with a depth of 1/2-2/3 of the stem thickness, and the cut length the same as the rootstock cut. Insert the scion cut into the cut on the rootstock stem, so that the two cut surfaces fit closely together, and fix the joint with a grafting clip. After about seven days, the joint heals; cut off the scion roots, and after 10-15 days remove the grafting clip.
Top insertion grafting using gourd as rootstock: When grafting, first remove the gourd terminal bud and true leaves, leaving only two cotyledons, then use a bamboo skewer with a tip having a 6-8 mm bevel and thickness comparable to the watermelon seedling, insert it downward along the direction of about 45 degrees between the gourd cotyledon veins and the gourd stem, with the skewer tip just exposed as the standard. Cut off the watermelon seedling stem diagonally with a blade at 8-10 mm below the cotyledons, with a cut surface length of 8~10 mm, pull out the bamboo skewer, and quickly insert the watermelon scion cut surface downward into the gourd rootstock, so that the two cut surfaces are pressed tightly together, with the rootstock cotyledons and scion cotyledons crossing in a “cross” shape.
Pest and disease control
The main diseases of watermelon include fusarium wilt, gummy stem blight, spot disease, anthracnose, downy mildew, powdery mildew, and phytophthora blight, etc. The main pests include cutworms, aphids, spider mites, thrips, red pumpkin beetles, tobacco cutworms, and melon webworms, etc. Fusarium wilt can be prevented by grafting and replacing the root system; for gummy stem blight, spot disease, anthracnose, etc., you can choose 70% thiophanate-methyl wettable powder 1000 times solution, 25% Amistar (azoxystrobin) suspension concentrate 1500 times solution, 50% Baoliduo wettable powder 2500 times solution, 70% Antaisheng wettable powder 600 times solution, 10% Shigao wettable powder 1500 times solution, etc. for spraying; for downy mildew and phytophthora blight, you can use 72% Kelu wettable powder 800 times solution, and Kejia suspension concentrate 1500 times solution for spraying; for powdery mildew, you can use 40% Fuxing emulsifiable concentrate 6000 times solution, and 25% triadimefon wettable powder 1500 times solution for spraying. To control aphids, thrips, and spider mites, you can choose 1% insecticidal emulsifiable concentrate 2500 times solution, 10% Yibianjing wettable powder 2500 times solution, etc. for spraying; to control melon webworm, you can use 5% Regent suspension 2500 times solution for spraying; to control tobacco cutworms and tobacco budworms, you can use 15% Anda emulsifiable concentrate 4000 times solution, Aolü No. 1 suspension concentrate 800 times solution, 10% Chujin suspension concentrate 1500 times solution, etc. for spraying.
As mentioned above, the sales volume of watermelon is very large every year, because watermelon has especially wide edible value. It can not only be eaten directly, but can also be made into watermelon juice, watermelon yogurt, and watermelon ice cream. Every summer, watermelon is in short supply, the prospects for growing watermelon are very promising, and increasing watermelon yield is also particularly important.