When to plant watermelon, what should I pay attention to?

Watermelon cultivation in the open field is cultivation without protective equipment. The climate varies greatly from place to place, so the sowing time is different. Because of the high temperature in the south, the sowing time is earlier, and the sowing time in the north is generally later, but the early ploughing time can also be sown earlier. In spring, when the local final frost has passed and the ground temperature is stable at about 65438 05℃, the suitable time for sowing in the open field is generally. The best sowing date should also be determined according to the variety, cultivation season, cultivation method and edible season.

2. Seed treatment and germination acceleration:

1) Sun-drying: Sun-drying for two noon to improve the germination ability of seeds.

2) Seed soaking: soak the dried seeds in warm water (about 30℃) for 6 hours, then take out the seeds, wrap them with towels or coarse cloth, wipe off the mucous membrane on the seed skin, soak them in 800 times of 60% Duofu or 70% sulfometuron-methyl wettable powder for 4 hours, take out the liquid medicine, and rinse them with clear water to prevent Fusarium wilt.

3) Accelerating germination: Put the soaked seeds flat on a wet towel, cover them with a layer of wet towel, and put them at a constant temperature of 33℃ to accelerate germination (if they don't germinate for 24 hours, then rinse them with clear water).

3. Preparations before broadcasting:

1) Land selection: Watermelon planting should choose plots with loose soil, good air permeability, convenient drainage and transportation. Watermelon fields cannot be continuously cropped, and it usually needs to be rotated once every 5-6 years. Otherwise, the blight will be very serious.

2) Selection of stubble: The previous stubble has great influence on the yield, quality and disease resistance of watermelon. Good previous crops can improve yield and quality, increase disease resistance and lay the foundation for high yield and bumper harvest. The first crop of watermelon planting is wasteland, followed by the second crop of wasteland and cereal crops, and the bean stubble and vegetable field are not ideal, so it is impossible to continuously crop melon stubble.

3) Soil preparation: In order to create a soil environment which is suitable for the growth and development of watermelon roots, it is necessary to cultivate deeply in Gua Tian, and it is best to turn the ground in winter. In the plot with deep ploughing or deep ploughing foundation, according to the row spacing of tillage, base fertilizer (broken ridge and sandwiched fertilizer) is applied in the subsoiling ditch to prepare the border for plastic film mulching or sowing.

4) Fertilization: Basic fertilizer is the basis of high yield of watermelon, and insufficient basic fertilizer will aggravate the anthracnose of watermelon, resulting in low yield and poor quality. According to the test results, the application of high-quality farmyard manure of 5,000 kg per mu not only has large melons and high yield, but also has less diseases, good quality and high commodity rate. If farmyard manure is not enough, biological bacterial manure can also be used as base fertilizer. If chemical fertilizer is used as base fertilizer, the ratio of nitrogen, phosphorus and potassium must be appropriate. The total absorption ratio of nitrogen, phosphorus and potassium in the whole growth period of watermelon is 3.28: 1: 4.33.

4. Sowing point:

Plastic film for watermelon planting can be planted first and then covered with plastic film, or covered with plastic film before planting.

1) sow first, and then cover with plastic film: plan a big pit on the whole boundary, sow in the middle of the pit, cover with soil for 2 cm and keep a small pit with a depth of 10 cm, and then cover with plastic film, so that each small pit becomes a simple "small greenhouse". This method of plastic film mulching is often used to protect seedlings in drought-resistant areas in order to go on the market early in early spring when the ground temperature is low. The advantages are early sowing, early emergence, early maturity and early listing. The disadvantage is that the seedlings are easy to grow in vain, and the seedlings will be roasted to death if they are not released in time, and the seedling survival rate is low.

2) Film mulching before sowing: In order to improve the ground temperature, cover the film in advance. When the ground temperature rises above 15℃, punch holes in the film and sow with an iron tube with a diameter of 5 cm. Sowing time is seven days before the end of the last frost (the last frost in spring), and wet soil cannot be used when covering soil, otherwise hard cover will appear. This method is simple, easy to cover with plastic film, and has high seedling protection rate. Generally, people who grow melons for the first time are easy to succeed.

5. Reasonable close planting:

Watermelon is a light-proof crop, which is planted too thinly, resulting in waste of soil fertility and serious loss of light leakage. Although sparse planting may increase the yield per plant, the population yield will decrease. Too dense planting, overlapping leaves, premature yellowing and shedding of lower leaves, weakened plant growth, reduced yield per plant and increased proportion of small fruits. Although the population yield may be slightly increased, the commodity rate and quality are reduced. The suitable density is row spacing 1.4m and plant spacing 0.7m. Intercropping and interplanting can increase row spacing to 1.8 ~ 2.0m and plant spacing 0.7m.. ..

6. On-site management:

1) Fertilization: Fertilization in Gua Tian should be "sufficient, precise and skillful", that is, sufficient base fertilizer, precise seed fertilizer and skillful topdressing.

Base fertilizer: it is the basis of high yield and an important measure to prevent diseases, which has a great influence on yield and disease resistance. The yield per mu in Gua Tian is 10,000 kg, which requires 5,000 kg of decomposed farmyard manure, 3-way compound fertilizer 15 kg, potassium sulfate 10 kg, 50 kg of cake fertilizer and 25 kg of calcium superphosphate, and is applied to land preparation and ridging.

Seed fertilizer: it can greatly promote the growth of seedlings, but the seedlings are small and require less fertilizer, so it is necessary to apply less refined fertilizer and avoid using more. The formula of nursery nutrient soil can be: weathered paddy soil 60%, pig cow dung residue crushed and screened, decomposed and screened 40%, granular compound fertilizer 0.2% (crushed carefully). Mix the three ingredients evenly and put them in a bowl. This nutrient soil formula can ensure the normal growth of watermelon seedlings, without burning seedlings, and the operation is simple and easy.

Topdressing: it is an important link in field management and one of the important measures to realize high-yield cultivation of melon. It must be clever topdressing. The method is topdressing water and fertilizer in dry days, supplying fertilizer with water, topdressing granular fertilizer in rainy days, and the ratio of urea to potassium fertilizer is 1: 1, and topdressing with a wooden stick with a diameter of 5 cm. The first topdressing is in the five-leaf stage, with the purpose of promoting plant growth, rapidly stretching vines, expanding assimilation area and laying a material foundation for flower bud differentiation. Three-element compound fertilizer 10 kg should be applied topdressing per mu. The second topdressing is seven days after flowering, in order to promote fruit expansion. Urea 15 kg and potash 15 kg should be topdressing per mu. The third topdressing was carried out 7 days after the second topdressing, and the application rate per mu was urea 10 kg and potassium fertilizer 10 kg.

2) Irrigation: Watermelon is a drought-tolerant crop, which is drought-tolerant and afraid of waterlogging, but it does not need irrigation, but it needs timely and appropriate irrigation.

Sowing and watering: When watermelon is sown or planted, ditch and water it. The amount of water is moderate, and only the sowing line is watered to meet the water demand for seed germination or planting survival.

Water for promoting seedlings: Watermelon is watered in combination with the first topdressing at heading stage, and the amount of water is moderate. Only the seedbed is watered to promote seedling growth, expand leaf area, and then intertillage to conserve moisture and promote root growth.

Watermelon swelling water: watermelon fruit enters the peak of fruit swelling after depilation, and the water demand increases. At this time, the temperature rises and the evaporation increases. In order to promote fruit expansion and prevent redundant seedlings, the water increase should be combined with secondary topdressing, and the water should be appropriately increased, and then watered according to soil quality and rainfall. Water swelling should be watered several times from depilation to a certain extent, and water supply should be balanced to prevent fruit cracking, especially after severe drought.

During the growing period of watermelon, how to judge whether there is water shortage according to the appearance of watermelon plants can be observed at noon on sunny days when the sun is strongest and the temperature is highest. At the seedling stage, if the leaves gather inward at noon and turn dark green, it means that the plants are short of water. After the watermelon is stretched, if the faucet turns up and the edge of the leaf turns yellow, it means there is more water. Observe the wilting of watermelon leaves during the fruit-bearing period. If the leaves wilt or wilt slightly, they will recover quickly, indicating that there is no water shortage. If wilting is too early, too long and recovery is slow, it means water shortage.

3) pressing vines, pruning, thinning fruits, selecting melons, fixing melons, and timely topdressing.

Pressing vines is an important work of watermelon field management. There are two ways to press rattan: open pressing and dark pressing. The function of vine pressing is to prevent wind-blown seedlings from damaging branches, leaves and fruits, control plant overgrowth, promote fruit setting, adjust the contradiction between long seedlings and fruit setting, promote the formation of adventitious roots, increase the absorption range of fertilizer and water, and ensure the uniform distribution of melons and vines on the ground. Generally, according to the three sections (lanes), when the main vine is 40 cm, according to the first section (lanes), and the second section (lanes) is about 100 cm. "Open pressure" means pressing melons and vines on the ground with clods, branches and other things. "Dark pressure" means digging a deep ditch in the ground, putting melons and vines in it, leaving only leaves, but compacting them with soil by hand. Exposure to stress is better in rainy areas.

Pruning and fruit thinning: it can adjust the contradiction between long seedlings and fruit setting and maintain the balance between nutrition and reproductive growth; Early fruit thinning promotes vegetative growth and prevents redundant seedlings; Leave more branches and leaves in the later period, enhance the fruit-setting ability, avoid empty seedlings without melons, and achieve the goal of high yield and harvest of big melons.

Three-vine pruning: leave one main vine and two strong side vines from the base, and cut off all the other side branches. Keep melons between nodes of main vine 10 ~ 18, one melon per plant, and do not need pruning after sitting.

In watermelon cultivation, selecting and fixing melons is the key to improve the quality and commercialization of commercial melons. For large fruit varieties, the third female flower of the main vine is selected to keep the melon, and a standard melon is determined for each plant, and careful management is carried out to make the watermelon reach the standard cultivation and harvest the standard fruit. Especially for multi-vine pruning, if melons are not fixed, the commodity rate of watermelon will inevitably decrease.

Timely topdressing is the key measure to improve the yield and quality of watermelon and promote the increase of watermelon. On the 7th day after the watermelon blooms, the fruit begins to expand rapidly, which is the key period for topdressing. Topdressing too early or too late will affect watermelon yield, watermelon size and watermelon commercialization, so topdressing should be done in time at this time. Generally, urea 15 kg and potassium sulfate 15 kg are applied topdressing per mu.

7. Timely harvest:

To judge the maturity of fruit, firstly, calculate the number of days of sitting melon according to the characteristics of varieties; Secondly, look at the appearance of the fruit. Mature watermelon has hard skin, clear pattern, inward contraction and depression of umbilicus and pedicel, most of the fluff on the handle falls off, and the tendrils dry before fruit setting. Third, listen to the sound of fruit. Click on the fruit with your finger to listen to the sound. It is the ripe melon that makes a "bang, bang" low dumb and turbid sound, and it is the ripe melon that makes a "bang, bang" crisp sound. Fourth, by feeling, hold the melon in one hand and pat it gently with the other. If the hand holding the melon has a slight shaking feeling, it is a ripe melon. You can also gently shake the handle when picking melons. Those who can easily remove the handle from the vine are usually ripe melons. According to the above methods, we can make a comprehensive judgment and harvest in time.