Watermelon Seedling Raising Time
Mastering the golden period for raising watermelon seedlings is the foundation for harvesting high-quality fruits. As a warm-loving crop, watermelon seedlings are highly sensitive to environmental factors such as temperature and humidity. Scientific seedling management can not only improve the seedling emergence rate but also lay a solid foundation for fruit setting in the later stage. The following text will explain in detail the timing and key points of raising watermelon seedlings.
Best Time for Watermelon Seedling Raising
Time Differences in Different Regions
In the North China region, it is recommended to start from mid-March to early April, when the ground temperature is stable at 15℃ or above. In the Yangtze River Valley, it can be advanced to late February, using small arch shed heating facilities. In the tropical southern regions, seedlings can be raised all year round, but it is necessary to avoid the rainy season.
Temperature Control Standards
Seed germination requires maintaining a daytime temperature of 28-30℃, and a nighttime temperature not lower than 18℃. During the seedling growth period, maintain a daytime temperature of 25-28℃, with a temperature difference controlled within 8℃. When the temperature is below 10℃ for three consecutive days, it is necessary to use double-layer film coverage for insulation.
Key Techniques for Watermelon Seedling Raising
Seed Treatment Steps
After sunning the seeds for 6 hours on a sunny day, soak them in warm water at 55℃ for 15 minutes. Then change to 30℃ clear water and soak for 8 hours. Wrap them in a wet towel and place them in a constant temperature incubator. When 70% of the seeds have shown white, they can be sown.
Substrate Preparation Points
Use a ratio of peat soil: perlite: decomposed cow dung = 6:2:2, and add 50g of carbendazim for disinfection per cubic meter. The moisture content of the substrate should be controlled at around 60%, with the ideal condition being able to form a ball when held in hand and scatter when dropped.
Seed Sowing Depth Standards
Use the spot sowing method, sowing 1 seed per hole, and covering the soil with a thickness of 1-1.5cm. Sowing too deep can make it difficult for seedlings to emerge, and too shallow can result in capillary seedlings. After sowing, water thoroughly and cover with plastic film to keep moisture.
Key Points of Watermelon Seedling Management
After the seedlings emerge, promptly remove the plastic film and maintain an average of 8 hours of sunlight per day. After the true leaves spread, spray 0.2% potassium dihydrogen phosphate every week. When the seedlings are 25-30 days old, with 3 leaves and 1 heart, they can be transplanted. During the hardening period, gradually increase the ventilation time to improve the seedlings' resistance to adversity.
By precisely grasping the seedling raising time window and配合 scientific temperature and humidity management, high-quality watermelon seedlings with thick stems and developed roots can be cultivated. Farmers should adjust management plans flexibly based on local climatic characteristics and variety traits.