When will watermelons be sown in the greenhouse

Greenhouse watermelon is a commonly used watermelon planting method, many melon farmers use this method to grow watermelons, so when to sow watermelons in the greenhouse?

Planting time of watermelons in greenhouse

The sowing time of watermelon in greenhouse is related to planting technology and watermelon varieties, three-film seedling usually began on January 10, four-film mulch began on December 20, and open-field watermelon usually began to grow on March 10.

Before sowing seeds, soaking seeds to accelerate germination, drying seeds for 2 days, and then disinfecting seeds. Soak the seeds in 55 ℃ warm water, stir for about 30 minutes, and continue soaking for 2 hours after cooling.

Medicament treatment usually uses formalin 100 times solution to soak seeds for 30 minutes, or 50% carbendazim 500 times solution to soak seeds for 1 hour, rinse with clean water and soak for 3-4 hours. Wash the treated seeds, germinate at 40 ℃ for 6 hours, accelerate germination at 33 ℃, and sow when the radicle grows to 0.5cm.

II. Planting techniques of watermelons in greenhouse

1. Land management

Watermelon in greenhouse is generally cultivated with high density, so soil preparation should be fine. The winter idle greenhouse should be ploughed 25 cm deep before winter and frozen to make the soil loose.

Generally, each mu of bottom fertilizer applies high-quality barnyard manure 4000kg to 5000 kg or fully mature chicken manure 3000kg to 4000 kg, calcium superphosphate 50kg, potassium sulfate 15kg to 20kg, fully mature cake fertilizer 100kg.

Half of the bottom fertilizer is fully spread and turned into the soil, and the other half of the soil is generally cultivated with small high ridges and high borders, with a row spacing of 1 to 1.2 meters. In the case of close planting of stents, grafting cultivation, double vines pruning and leaving 1 melon per plant, small high ridges were made according to the row spacing of 1 meter. When creeping on the ground, it can make a border in the north-south direction (longitudinally parallel to the greenhouse).

2. Transplanting

Under the condition of covered with 3 layers of film, watermelon in greenhouse is about 10 days dry planting than double mulching cultivation in arch greenhouse, and its density is higher than that of double mulching cultivation in arch greenhouse, and requires careful pruning. Those cultivated with close planting on scaffolds are denser than those cultivated on the ground.

3. Temperature and light

Temperature: 5-7 days after planting watermelons in the greenhouse, attention should be paid to raising the ground temperature. If the daytime temperature in the shed is higher than 35 ℃, efforts should be made to block the light and cool down. After slowing down the seedlings, ventilation can be started to adjust the temperature in the shed. Generally, the temperature in the shed should not be higher than 32 ℃ in daytime and 15 ℃ at night.

When the melon vine is about 31 cm long, the small arch shed in the greenhouse can be removed. During the full flowering period of watermelon in greenhouse, sufficient light and higher night temperature should be maintained, because if the night temperature is lower after artificial pollination, it will affect the expansion of watermelon and cause watermelon to fall. When the external temperature exceeds 18 ℃, ventilation should be increased, and the skylight and both sides of the greenhouse should be opened for ventilation at the same time, so that the daytime temperature in the greenhouse is not higher than 30 ℃, so as to prevent the excessive temperature difference between day and night, which leads to the deterioration of watermelon meat and the decline of watermelon quality.

Lighting: adjustment of gas composition in the shed. Under the airtight condition of greenhouse, the content of carbon dioxide in the air is seriously insufficient, which affects the normal progress of photosynthesis and the accumulation of assimilation products. The application of carbon dioxide gas fertilizer can increase the concentration of carbon dioxide in the greenhouse and supplement the content of carbon dioxide in the greenhouse.

Increase the amount of daylighting. Watermelons require strong light. However, because the surface of the greenhouse film is dewy or unclean, the light intensity in the greenhouse is often reduced, especially in the case of multi-layer covering. Therefore, attention should be paid to keeping the greenhouse film clean and not using the old film with poor light transmittance.

4. Pruning and pollination

When the watermelon grows to a certain extent, it is necessary to prune, frame and bind the vine, and then carry out artificial pollination so that the watermelon can grow healthily.

5. Topdressing and watering

During the period of watermelon planting, topdressing and watering should be carried out reasonably, and the amount of water in the early stage of watermelon in greenhouse should not be too large. After slowing down the seedlings, if the ground is not dry, it can not be watered; if it is too dry, it can be watered once along the ditch.