When will watermelons be planted in the greenhouse? Have you really mastered the technique of growing watermelons in greenhouse?

Watermelon cultivation in greenhouse belongs to fine and intensive cultivation with strong technicality. only by taking comprehensive measures can we achieve the goal of early maturity, high yield and high benefit. So when will watermelons be planted in the greenhouse? What are the planting techniques and methods of watermelon in greenhouse?

When will watermelons be planted in the greenhouse?

If it is covered with four films, it can start on December 20; three-film seedlings should not be raised too early, starting on January 10; two-film (plastic film + small arch film) seedlings are raised around February 20; open-field watermelon seedlings are raised around March 10. Before and after the Qingming Festival, the seedling age is generally required to be 35-45 days, 2 leaves a core-3 leaves a core when transplanting, you should make reasonable arrangements according to stubble, soil and facilities.

II. Techniques and methods of planting watermelons in greenhouse

1. Soil preparation and fertilization

Watermelon in greenhouse is generally cultivated with high density, so soil preparation should be fine. If you are using the winter greenhouse, you should plough 25 centimeters deep before winter and freeze the soil 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 and planting

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 management

Five to seven 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.

4. Lighting management

(1) 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.

(2) 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.

5. Pruning and binding vines

(1) pruning. Watermelons in greenhouse should be strictly pruned under the condition of close planting. When the length of the main vine is 30cm to 50cm, the lateral vine has protruded obviously. when the lateral vine grows to 20cm, a strong lateral vine is left, and the rest is removed completely. After that, the lateral vine growing on the main vine and lateral vine should be removed in time, leaving 10 leaves on the top of the melon node and then topping. The pruning work should be carried out before the melon sits. When using close planting with support, the work of removing lateral vines should be carried out until the melon seedlings are full and topped. Remove tendrils as well as lateral vines.

(2) framing and binding vines. Bamboo poles and hanging ropes can be used when erecting, but bamboo poles are better, because bamboo poles are not easy to cause watermelons to fall. 20 days after watermelon planting in the greenhouse, the length of the main vine is about 30 centimeters. After removing the small arch shed in the greenhouse, immediately carry on the transplanting rack. Each melon seedling is planted with two bamboo poles, which are inserted on both sides of the plant, 10 centimeters away from the root of the plant, and the bamboo pole should be firmly and upright. After the rack is inserted, the vines are introduced and tied.

6. Artificial pollination

Pollination should be carried out at 8: 9 a.m. If the male flower spreads powder late in cloudy days, it can be postponed appropriately. In order to prevent the male flowers from being pollinated late on a cloudy day, the male flowers that can open the next day can be taken back in the afternoon the day before, and put indoors in a dry and warm place, so that they can blossom on time the next morning, and then use this flower to pollinate the female flowers. Pollination should begin with the second female flower in order to retain melons.

7. Choose and hang melons

In order to improve the weight of the single melon and make the melon shape correct, the melon sitting on the second female flower should be selected. if the melon is left too early, the melon is small and the shape is not correct, and too late is not conducive to the early listing. Generally, 3-5 days after pollination, the melon fetus grows obviously, it is necessary to give priority to leaving melons on the main vine, but not on the main vine, but on the side vines. In the use of close planting bracket cultivation, when the melon grows to such as the mouth of the bowl, the melon should be suspended in time to prevent the young melon from falling.

8. Topdressing and watering

The amount of water should not be too large in the early stage of watermelon in greenhouse. 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.

In addition, it should be noted that the flowering and fruit-setting period is not watered to prevent overgrowth and promote melon-setting.