The difference between watermelon cultivation in greenhouses and open field cultivation is that the planting area is smaller. Therefore, how to extend the melon-bearing time, produce more melons, and increase the yield per unit area is an urgent problem in greenhouse watermelon planting. Today, Xin Nongming will introduce to you a greenhouse watermelon planting method that increases yield. This is a cold shed watermelon method. The sow three harvest technique is very popular here.

1. Construction of cold sheds

Cold sheds should be selected on high-lying soil plots with deep soil, good permeability, capable of being irrigated in drought conditions, and able to be drained in flood conditions. For construction, it is best to plow deeply before winter. The plowing depth should reach more than 25 cm. The scaffolding should be set up before the soil freezes. The shed is generally designed to be 40 meters long, 6.4 meters wide, and 1.9 meters high, leaving 1.2 meters between the two sheds. meters to make drainage ditches.

2. Cultivate strong seedlings

The seedling age of watermelon is generally 30 to 35 days. Therefore, sowing and raising seedlings usually begins in mid-to-late January.

1. Prepare the seedbed

Before sowing, the seedbed must be prepared. In order to facilitate transplanting and planting, melon farmers can slightly modify the planting shed to start raising seedlings. First lay a layer of plastic film on the flat seedbed, then lay a layer of straw curtain, and then lay a layer of plastic film on the straw curtain. The plastic film and straw curtain can isolate the seedling tray from the soil, which can play a good role. The upper and lower layers of plastic film can protect the middle straw curtain from becoming rotten quickly.

Insulation alone is not enough, so the temperature of the seedbed at night will not meet the requirements for seedling cultivation. Therefore, electric wires must be laid on the plastic film to heat the seedbed. The heating wires are laid longitudinally along the seedbed. Since the temperature in the nursery shed is low at this time, the heating wires can be laid more densely, one every 8 to 10 centimeters. After the seedling trays are filled, the excess parts of the upper and lower layers of plastic film on the straw curtains can be removed. Turn it up onto the seedling tray, compact the edges with soil, and finally cover the seedbed with a layer of plastic film and a layer of straw curtains on top. In this way, when sowing the next day, the seedlings will not be too dry or dry. It will be too cold.

The next day, lift off the film and straw curtain on the seedling tray, press the sowing hole with your fingers, and then sow the seeds.

2. Sowing

After sowing is completed, cover the seedling tray with soil until the thickness of the soil is even with the seedling tray. In order to prevent the occurrence of diseases in the seedling stage, spray the seedbed with 1000~2000 times of 99 Hymexazine wettable powder. This not only prevents diseases, but also adds moisture to the seedbed, which is beneficial to the germination of watermelon seeds. After sowing, cover the seedling tray with plastic film, cover it with a straw curtain, and turn on the electric hotline at night.

Cultivation of strong seedlings is the basis for extending the growth period of watermelon and preventing premature plant aging. After sowing, the electric wire should be turned off during the day and the straw curtain on the seedbed should be opened to allow the seedbed to receive direct sunlight. However, the plastic film does not need to be removed at this time to maintain a suitable germination temperature. Before emergence, the daytime temperature should be maintained at 32~35°C. When the temperature drops in the evening, cover with straw curtains and use heating wires to increase the temperature. The night temperature should be controlled above 25°C. It will take about 3 days for the seeds to germinate.

3. Seedling management

①Temperature management

After the seedlings emerge, remove the plastic film on the seedbed and build a small shed on the seedbed to keep the seedlings warm. During the period from when the first true leaves are exposed, the temperature should be lowered appropriately to prevent the seedlings from growing too tall and forming tall seedlings. During the day, the temperature can be controlled between 25 and 28°C by closing or opening the small arch shed. At night, the small arch shed can be closed and covered with straw curtains to keep the temperature above 18°C. Do not water until the first true leaves unfold.

②Water and fertilizer management

Plug matrix seedlings have a small nutritional area, which can easily cause yellow and weak seedlings. Therefore, nutrients must be replenished in time. After the first true leaves unfold, spray a mixed solution of 0.1 potassium dihydrogen phosphate solution and 0.3 urea every 5 to 7 days. After the first true leaf unfolds, water management must follow the principle of seeing dry and wet, that is, do not water until the seedling soil is dry. The plug tray should be watered thoroughly every time you water, so that the drainage holes of the seedling tray are until the water overflows.

③Low temperature seedling hardening

When the two true leaves of the seedlings have expanded, they can be transplanted. Seedling hardening should be carried out 5 to 7 days before planting, and ventilation time and volume should be gradually increased. The temperature should be maintained at 20 to 25°C during the day and 10 to 12°C at night.

3. Preparations before transplanting and planting

1. Land preparation and fertilization

A three-harvest watermelon has a long growth period and requires more nutrients. , so you must apply enough base fertilizer, especially organic fertilizer with a long fertilizer effect. The amount of base fertilizer should generally be controlled at 1.5 times that of conventional fertilization. Generally, 6000~8000kg of high-quality decomposed organic fertilizer, 100~150kg of cake fertilizer, 100kg of superphosphate and 25kg of potassium sulfate are applied per acre. If the soil fertility is poor, you can apply more, and if the soil fertility is good, apply less.

In order to better exert the fertilizer effect, a layered fertilization method should be used. Dig two 30 cm deep trenches on both sides of the shed center 1.5 meters away from the center of the shed, that is, near the planting site. Apply decomposed organic fertilizer to the bottom of the trench, backfill with 15 cm of soil, then apply cake fertilizer and fill it with soil. Superphosphate and potassium sulfate are applied to the border surface and finally leveled.

Due to the different durations of organic fertilizers, cake fertilizers and chemical fertilizers, chemical fertilizers are quick-acting fertilizers and can provide sufficient nutrition for seedlings after planting; the duration of cake fertilizers is longer than that of chemical fertilizers; the duration of organic fertilizers is longer than that of chemical fertilizers. Longest lasting. In this way, as the root system develops and goes down, it can get the nutrients it needs at different stages and delay the premature aging of the plant.

2. Laying out drip irrigation

A shed should have two rows vertically, with a 40cm wide sidewalk between the two rows. In order to prevent the ground temperature from dropping too much during watering, planting should be done Drip irrigation equipment is installed on the plot. The diameter of the drip irrigation pipe is between 2.5 and 3 cm, and the diameter of the water outlet hole is 1 mm. Since the border is wide, in order to ensure even watering, two drip irrigation pipes should be laid evenly in each border.

3. Spray herbicides

Weeding is also a task that must be done before planting. Use 100~150ml of 48 trifluralin EC or 33 pendimethalin EC per acre, and add water. 40~50kg, spray evenly on the soil surface. After spraying the herbicide, cover it with mulch and seal the greenhouse, and use sunlight to increase the temperature of the greenhouse.

3. Transplanting and planting

1. Planting

When planting, the seedlings should not be raised too early, but after 8 a.m. to prevent the seedlings from growing. Seedlings are frostbitten, because the outside temperature is still relatively low at this time, so planting should be done in the morning on a sunny day. The seedlings must be planted immediately after being transported to the planting location.

Before planting, a planting pit should be dug in the middle of the border. A row of planting pits should be dug in each border. The distance between the pits is 30 to 35 centimeters. After the planting pits are dug, planting can begin. After the planting is completed, the planting water should be poured immediately. Watering the planting water can increase the moisture content of the soil. It can not only provide sufficient water for the seedlings to slow down the seedlings, but also provide a certain amount of moisture for the expansion of the vines. The requirements for pouring the planting water are: It should be watered evenly and thoroughly, and the planting water should be poured for 2 hours.

2. Management of seedling slowing period

After planting, watermelon seedlings need to go through a period of slowing down. The slowing seedling period refers to the time from the time when the melon seedlings are planted to when they grow new leaves. period of normal growth.

The climate in spring is unstable, and there are often continuous cloudy days and cold weather in late spring, which causes the temperature in the shed to drop too much, which can delay the growth of seedlings at best, and can even cause melon seedlings to freeze to death in severe cases. . Therefore, management during the slow seedling period is very critical.

(1) Temperature management

After planting, you must first build a small arch in the shed for heat preservation. Generally, no ventilation is allowed in the first 3 days after planting. Both the shed film and the small arch shed film should be covered, and the temperature inside the shed should be increased as much as possible. The temperature inside the shed should be kept at about 32°C during the day and above 18°C ??at night.

After 3 days, the membrane of the small arched shed should be opened during the day to increase the light. The temperature in the shed should be controlled at about 28°C during the day. If the temperature exceeds 35°C, the membranes on both sides of the greenhouse should be opened appropriately to let in the wind. The sun sets in the afternoon. Close the air vents and small shed membranes in advance to keep the night temperature above 15°C. After about 5 to 7 days, the seedlings can be slowed down.

(2) Pour water to slow down the seedlings

After watermelon seedlings are slowed down, you should pour water to slow down the seedlings. The main function of watering the water to slow down the seedlings is to provide water for the spreading vines and at the same time promote the connection between the roots and the seedlings. Close contact with the soil facilitates rooting and water absorption. In order to promote the growth of seedlings, root-promoting water should be applied once with the seedling slowing water. Mix the soil Xiucai microbial agent containing more than 10 billion effective live spores per gram into a 100-fold solution and apply it with the water. This will have a great impact on the rooting of the seedlings. Good promotion effect.

Watering should be done on a sunny day, and the watering time should be arranged within 2 to 3 hours before and after noon. It must not be done in the evening to prevent the night temperature from dropping too low and affecting the melon seedlings. grow. When the temperature in the shed stabilizes above 15°C, the small shed can be removed.

4. Field management after transplanting and seedling slowing

The period from when the melon vine grows 6 to 7 true leaves to when the female flowers bloom in the fruiting part is the spreading period, which is about It takes about 20 days.

1. Management during the spreading period

After entering the spreading period, the growth of the above-ground parts accelerates, new leaves continue to unfold, and the lateral vines at the lower part of the plant also begin to elongate. The vine extension period is a critical period for the plant from vegetative growth to reproductive growth, especially from the initial flowering stage of male flowers to the late vine extension period from the blooming of the second female flower on the main vine.

At this time, if vegetative growth is too strong, it will inhibit the transformation to reproductive growth, affect the formation of flowers and fruits, and even cause a large number of flower and bud drop. Therefore, in order to make the relationship between nutrition and reproductive growth Coordination, vegetative growth should be properly controlled to prevent the stems and leaves from being sealed due to vigorous growth.

To prevent the occurrence of sealed rice seedlings, we must first lower the temperature appropriately, keeping the temperature between 25 and 26°C during the day and above 15°C at night. In addition to temperature, water and fertilizer control and reasonable pruning and vine management are also required. During this period, it is necessary to ensure that the rhizosphere soil of the melon seedlings is moist and neither dry nor watered to achieve the purpose of controlling water and strengthening the seedlings.

There is no need to fertilize during the spreading period. The outside temperature at this time is still relatively low. In order to maintain heat, the greenhouse is kept in a closed state most of the time with little or no ventilation. In this way, there will be a serious lack of carbon dioxide in the greenhouse. And the stems and leaves are in the vigorous growth period, and the leaf area increases rapidly. The lack of carbon dioxide will affect photosynthesis, and in severe cases will cause stunting of the plant. Therefore, it is necessary to apply more carbon dioxide gas fertilizer. You can hang carbon dioxide gas according to the density in the instructions. bag. As the plant grows, pruning should be carried out in time.

A three-harvest method generally uses the double-vine pruning method, that is, when the watermelon vine grows to 1 meter long, the main vine and a side vine with 3 to 5 nodes are retained, and the rest are Side vines must be removed. The remaining main vines serve as the fruiting branches of the first melon crop, and the side vines serve as vegetative branches.

When pruning, the direction of the main vine should also be adjusted to the side of the sidewalk, and the side branches should be in the opposite direction to the main vine. This will facilitate future management. Pruning work should be carried out continuously, and new vines growing on the main vines and side vines should be knocked off at any time. The main vines are pruned until the fruits are set, and the side vines are pinched when they have about 20 leaves to reduce the nutritional consumption of the melon vines during the fruit setting period and facilitate the early release of the first melons.

When the main vine grows to 12 leaves, the female flowers begin to appear, and then the management of the fruiting period begins.

2. Management during the fruiting period

(1) Temperature management

After watermelon enters the fruiting period, the ideal daytime temperature is between 28 and 30°C. The night temperature should be maintained between 18 and 20°C to ensure normal flowering and fruiting of the plants.

(2) Artificial pollination

Due to the low temperature at this time, there is no activity of pollinating insects, and the air flow in the shed is poor, it is difficult to rely on natural pollination to hold the melons. Yes, this problem can be solved by artificial pollination of flowers.

Artificial pollination is usually carried out between 8 and 10 am. Since the temperature at this time is still relatively low, if the pollination temperature is lower than 18°C, the first crop of melons will encounter more deformities. , so after the fruits sit, the development of the fruits should be checked. If any deformed melons are found, they should be removed immediately, and flowers should be selected for pollination on this branch to prevent empty seedlings.

(3) Water and fertilizer management

When the watermelon fruit grows to the size of a fist, it is necessary to pour melon-expanding water once and apply melon-expanding fertilizer once.

Supplementing potassium at this time will significantly improve the taste of watermelon, so potassium fertilizer needs to be applied again this time. Apply 20kg of compound fertilizer with a nitrogen, phosphorus and potassium nutrient ratio of 16:6:23 per acre with water. Water should be poured enough when watering, and drip irrigation should be provided for 2 hours. After this watering, water once every 5 days or so for 20 minutes each time, and stop watering 1 week before harvesting.

The first crop of watermelons is just the beginning of victory, and a third harvest is yet to come. However, if you want to achieve three gains, the subsequent management may surprise you. This approach looks more like sabotage to outsiders.

(4) Second-crop melon field management

①Cutting vines

After the watermelon plant bears fruit, it will consume a lot of nutrients, resulting in weak plant growth and affecting the second crop. The growth of stubble melons, and watermelons have the ability to regenerate. If the old plant is used as the mother plant and new branches are produced after pruning, it can effectively solve the problems of aging of the old plant, poor ventilation and light transmission, reduced yield, and poor quality, and make the watermelon grow again. Forming a production peak to achieve the purpose of extending the watermelon supply period.

The branches and vines at this time still look relatively strong, and there should be no problem in growing another melon, but why do we choose to cut the vines at this time? Because the second crop of melons has been harvested, it has entered July. At this time, the temperature is relatively high and rainfall is heavy. This is a period when diseases and insect pests occur seriously, which will cause weak growth of new branches, difficulty in fruit setting, high empty seedling rate, and low yield. This is the reason why the vines are not cut after the second crop of melons are harvested.

Cutting vines does not mean cutting off all the old vines, but only cutting the main vines and retaining the side vines. The method is to leave 10 cm of old vines at the base of the main vines and cut off the rest. If it falls off, the old vines left behind usually have 3 to 5 latent buds.

②Pests and diseases control

Although there are fewer pests and diseases at this time, they cannot be ignored. After cutting the vines, scientific control can be carried out according to the actual conditions in the field.

③ Fertilization to promote growth

After cutting the vines, in order to promote the germination of new branches, watering and fertilization are also required. Apply 20kg of urea per acre with water to promote the growth of new branches and leaves. grow.

About a week after cutting the vines, new vines will grow from the base of the old vines, leaving a strong new branch as the fruiting branch, and the original side vines continue to serve as vegetative branches. According to the management method introduced earlier, the second crop of melons can be harvested in less than 2 months.

(5) Field management of the third crop of melons

After the second crop of melons are harvested, the third crop of melons will be left. The management this time should be simpler than the management of the first two crops of melons. Because the growth potential of the melon vines is relatively weak at this time, only one melon can sit on each melon vine, and other fruits will melt away during development due to insufficient nutrient supply. Therefore, the principle of keeping the third crop of melons is to let them grow and retain the fruits naturally.

①Pruning branches

After a long period of growth, the canopy closure in the field will become more serious, which will not only affect the fruit setting of watermelon, but also aggravate the occurrence of diseases and insect pests. After the third crop of melons is established, half of the seedlings and vines that are not fruit-bearing branches should be cut off, and 3 to 4 leaves should be left on the fruiting branches for topping. This can significantly improve the ventilation and light transmission conditions in the field and ensure the third crop of melons. of normal growth.

②Spray foliar fertilizer

After several months of growth, the watermelon plant will show obvious senescence. Therefore, during the expansion period of the third crop of melons, in addition to fertilizing and watering the soil as described above, 0.1 potassium dihydrogen phosphate solution must also be sprayed on the leaves. Provide enough nutrients for watermelon fruit to expand. In this way, the third crop of melons can be harvested in mid-to-late August.

Cold shed watermelon is a three-harvest planting technology. Although the melon farmers have worked hard, the harvest is quite good. With the promotion of this technology, more and more melon farmers will benefit from it. More revenue.