Detailed Guide to High-Yield Watermelon Cultivation in Solar Greenhouses (Part 1)
High-Yield Watermelon Cultivation Techniques in Solar Greenhouses (Part 1)
1. Variety Selection
Jingxin watermelon, Jingfeng No. 1, Jingfeng No. 2, Zaojia (8424), etc. Their characteristics are disease resistance, tolerance to low temperatures, tolerance to weak light, good quality, and high yield.
2. Grafting and Seedling Raising
(1) Making the Seedbed
Set up a raised bed or an electric heating bed inside the greenhouse. For each mu of watermelon, build a seedbed 1.2 m wide, 10 cm deep, and 7 m long, and place nutrient pots filled with nutrient soil, 10 cm x 10 cm, closely into the seedbed. The nutrient soil is made by mixing decomposed organic fertilizer and fertile garden soil at a ratio of 1:3. Water thoroughly to saturate the bottom, then cover with film to increase temperature.
(2) Soaking Seeds and Promoting Germination
Soak the rootstock (gourd) seeds first in 70°C hot water, stir and cool to 30°C, then soak at constant temperature for 6 hours, and promote germination at 25°C-30°C. For the scion (watermelon), the sowing rate per mu is 75-100 g. Disinfect with 55°C warm water, stir and cool to 30°C, soak at constant temperature for 6 hours, then keep warm and moist at 30°C and promote germination in darkness for 12-24 hours.
(3) Sowing
Watermelons in solar greenhouses are generally sown and raised as seedlings in early December. When gourd is used as the rootstock, the insertion grafting method is used. The rootstock and watermelon scion should be sown at staggered times. After the rootstock is sown for 4-5 days, soak and germinate the watermelon seeds. When the radicle grows to 0.2-0.5 cm, sow into nutrient pots and cover with 1.5 cm of soil. After sowing, keep the seedbed temperature at 25°C-30°C during the day and above 15°C at night. Seedlings emerge after 7-8 days. When the seedlings grow to 5 cm, spray water and insecticide. 1-2 days after emergence, graft when the cotyledons unfold.
(4) Management After Grafting
Within 3-4 days after grafting, shade the plants, keep them warm and moist, maintain the temperature at 26°C-28°C during the day and 15°C-18°C at night, with relative humidity above 90 percent. If necessary, spray once at noon. After 3 days, gradually increase light exposure and ventilation to lower the temperature; only shade at noon, and control the temperature at 22°C-25°C during the day and 18°C-20°C at night. Prevent excessively high temperatures and insufficient light, which can cause leggy seedlings. Especially from the first true leaf to the unfolding of the fourth true leaf, increase ventilation and maintain a day-night temperature difference of more than 10°C to ensure normal flower bud differentiation.
3. Field Planting
(1) Land Preparation and Application of Base Fertilizer
Deeply plow and finely harrow the land, open furrows at 1 m row spacing, apply 3000 kg of high-quality farmyard manure, 50-75 kg of superphosphate, 10 kg of potassium sulfate, and 10-15 kg of ammonium sulfate into the furrows, and mix the manure evenly with the soil. Then open furrows on both sides and build ridges with a bottom width of 50 cm, a top width of 35 cm, and a height of 10 cm. Level the ridge surface, cover with plastic film, and then plant.
(2) Planting Method
Plant on a selected morning with good weather. At a plant spacing of 50 cm, cut a cross-shaped opening in the plastic film at the center of the ridge, pull the four sides open, use a trowel to dig a hole and pour planting water, set the seedlings in water, and after the water seeps in, cover with soil, pull the plastic film back into place, and seal the gaps tightly with moist soil.
Jingxin watermelon, Jingfeng No. 1, Jingfeng No. 2, Zaojia (8424), etc. Their characteristics are disease resistance, tolerance to low temperatures, tolerance to weak light, good quality, and high yield.
2. Grafting and Seedling Raising
(1) Making the Seedbed
Set up a raised bed or an electric heating bed inside the greenhouse. For each mu of watermelon, build a seedbed 1.2 m wide, 10 cm deep, and 7 m long, and place nutrient pots filled with nutrient soil, 10 cm x 10 cm, closely into the seedbed. The nutrient soil is made by mixing decomposed organic fertilizer and fertile garden soil at a ratio of 1:3. Water thoroughly to saturate the bottom, then cover with film to increase temperature.
(2) Soaking Seeds and Promoting Germination
Soak the rootstock (gourd) seeds first in 70°C hot water, stir and cool to 30°C, then soak at constant temperature for 6 hours, and promote germination at 25°C-30°C. For the scion (watermelon), the sowing rate per mu is 75-100 g. Disinfect with 55°C warm water, stir and cool to 30°C, soak at constant temperature for 6 hours, then keep warm and moist at 30°C and promote germination in darkness for 12-24 hours.
(3) Sowing
Watermelons in solar greenhouses are generally sown and raised as seedlings in early December. When gourd is used as the rootstock, the insertion grafting method is used. The rootstock and watermelon scion should be sown at staggered times. After the rootstock is sown for 4-5 days, soak and germinate the watermelon seeds. When the radicle grows to 0.2-0.5 cm, sow into nutrient pots and cover with 1.5 cm of soil. After sowing, keep the seedbed temperature at 25°C-30°C during the day and above 15°C at night. Seedlings emerge after 7-8 days. When the seedlings grow to 5 cm, spray water and insecticide. 1-2 days after emergence, graft when the cotyledons unfold.
(4) Management After Grafting
Within 3-4 days after grafting, shade the plants, keep them warm and moist, maintain the temperature at 26°C-28°C during the day and 15°C-18°C at night, with relative humidity above 90 percent. If necessary, spray once at noon. After 3 days, gradually increase light exposure and ventilation to lower the temperature; only shade at noon, and control the temperature at 22°C-25°C during the day and 18°C-20°C at night. Prevent excessively high temperatures and insufficient light, which can cause leggy seedlings. Especially from the first true leaf to the unfolding of the fourth true leaf, increase ventilation and maintain a day-night temperature difference of more than 10°C to ensure normal flower bud differentiation.
3. Field Planting
(1) Land Preparation and Application of Base Fertilizer
Deeply plow and finely harrow the land, open furrows at 1 m row spacing, apply 3000 kg of high-quality farmyard manure, 50-75 kg of superphosphate, 10 kg of potassium sulfate, and 10-15 kg of ammonium sulfate into the furrows, and mix the manure evenly with the soil. Then open furrows on both sides and build ridges with a bottom width of 50 cm, a top width of 35 cm, and a height of 10 cm. Level the ridge surface, cover with plastic film, and then plant.
(2) Planting Method
Plant on a selected morning with good weather. At a plant spacing of 50 cm, cut a cross-shaped opening in the plastic film at the center of the ridge, pull the four sides open, use a trowel to dig a hole and pour planting water, set the seedlings in water, and after the water seeps in, cover with soil, pull the plastic film back into place, and seal the gaps tightly with moist soil.