Technical points of raising Seedling to improve Fruit setting rate and quality of Watermelon

Watermelon seedling cultivation refers to sowing and cultivating seedlings in advance in protective facilities and transplanting them to the field when the external conditions are suitable. The more commonly used ones are greenhouse seedling raising, greenhouse seedling raising and small arch greenhouse seedling raising. Raising watermelon seedlings can increase fruit setting rate, reduce diseases and insect pests, increase production and income, save seed consumption and reduce expenses. Watermelon seedlings need certain equipment and higher technology, so we should pay attention to several points:

Watermelon seedling

1. The preparation of bed soil: the nutrient soil is required to be fertile, loose, water and fertilizer-free, free of germs, insect eggs, weed seeds, and can make big field soil, paddy field soil, river mud, furnace ash, cattle and horse dung, poultry manure and so on. The proportion of soil and organic fertilizer is 7-50% and 3-50% respectively. At the same time, 0.25 kg of urea, 1 kg of superphosphate (phosphate fertilizer), 0.5 kg of potassium sulfate, or only 1.5 kg of nitrogen, phosphorus and potassium three-element compound fertilizer are added to each cubic meter of bed soil to achieve nutritional balance.

2. The watermelon seeds used must be accelerated to sprout and disinfect, and a single seed should be sown in a nutrition bowl (block) and covered with 0.8-1cm to ensure smooth emergence and normal growth.

3. In order to improve the ground temperature, weeds, cow and horse dung, sawdust or layer ground hotline can be added under the seedbed soil. Double membranes can be used on the ground.

4. Higher bed temperature is required from seed sowing to unearthing, generally 28-30 ℃ in sunny days and 25 ℃ in cloudy days. If the temperature is low, the unearthed time will be prolonged, the seed consumes too much nutrients, and after emergence, it becomes thin and yellowing, which reduces the resistance. After the cotyledons are unearthed, the cotyledons should be cooled properly, 22-25 ℃ in sunny days and 18-20 ℃ in cloudy days, so as to prevent them from growing into tall seedlings. When 90% of the watermelon seedlings grow the first true leaf, it is raised to 25-27 ℃ and gradually reduced to about 20 ℃ a week before planting. Squat seedlings are carried out until the temperature is the same as the outside world.

5. Humidity: when sowing, after watering the bottom water, it is generally not watered until before emergence. In the cotyledon flattening stage, the ground was dry and wet, and the main purpose was to preserve soil moisture. A thin layer of fine sand can be spread on the seedbed to reduce soil water evaporation and prevent sudden collapse and blight. The relative humidity of the air should be maintained at about 80%. When the real leaves grow, if the ground is dry, you can use a spray can to spray water, which is carried out in the morning on a sunny day. As the temperature rises, the amount of water sprayed can increase gradually, generally every 3-5 days, until it stops 5 days before planting.

6. Lighting: use the new film as much as possible, keep the cleanliness of the film, increase the light transmittance, uncover the film early and cover it late under the permissible bed temperature. If you use double film, you should take off one layer during the day and cover it at night.

7. Loosen the soil: when the melon seedlings come out completely, loosen the soil on the bed surface, not too deep, so as to prevent damage to the root system. It is generally about 1cm, which can improve soil permeability, promote root growth, adjust humidity and increase bed soil temperature. When the true leaves grow out, loosen the soil again, which is conducive to the cultivation of strong seedlings, generally 1-2 days after each watering, loosen the soil once.

8. Prevention and control of diseases and insect pests: the main disease of watermelon in seedling stage is quenching disease, which can be prevented by dichloronitrobenzene, seedling fungus enemy, pentachloronitrobenzene, benzoin zinc, etc., and the main pests in watermelon seedling stage are mole cricket, aphids and so on.

9. 5-7 days before planting, begin to refine seedlings and stop watering and fertilizing. Increase ventilation, gradually make watermelon seedlings adapt to the natural environment and improve the survival rate. The best time for transplanting is when 2-3 true leaves are unfolded.