How to Grow Watermelons for High Yield? Latest Cultivation Techniques and Methods Tutorial

What is the most enjoyable thing about summer? Nothing beats “turning on the air conditioner under a quilt, watching a movie and eating watermelon”. Indeed, watermelon has almost become synonymous with summer; the thought of summer brings to mind summer watermelon. Watermelon quenches thirst, promotes salivation, clears heat and relieves summer heat, making it one of the fruits commonly kept at home in summer. For farmers, watermelon is also a good planting choice, so how can watermelon be grown for high yield? What are the key points of watermelon cultivation? The following is introduced by Qinnong Net for everyone: the technical key points of high-yield watermelon cultivation.

The cultivation process of any agricultural product cannot do without the five basic steps of site selection——seed selection——sowing——applying water and fertilizer——harvest, and watermelon is no exception. What this article introduces for everyone are the three key periods after adequate preparatory work such as site selection and seed selection has been done, specifically introduced as follows:

I. Sow and germinate at the right time, and carefully raise seedlings and transplant

1. Sowing period. Open-field sowing is best in mid-to-late April; if the supply period is to be delayed, sowing can be done in early June; if insulated seedling raising is used to advance the supply, sowing can be done in late March to early April.

2. Seed quantity. Use 1—1.5 liang of seed per mu of field; hybrid watermelon seeds are larger, so use 2—2.5 liang of seed per mu of field.

3. Seed soaking and germination. First soak the seeds in 50—55°C warm water (if there is no thermometer, use two parts boiling water plus one part cold water) for 15—20 minutes, then add a small amount of cold water to bring the water temperature down to about 30°C, wait for the water to cool naturally and soak for 2—3 hours, then put the soaked seeds into a small cloth bag, wash them clean with clear water and dry them, mix with an equal amount of clean wet river sand, wrap them in cloth and spread them flat to about one finger thick for germination. The suitable temperature for watermelon seed germination is 30—35°C; they can also be placed in a 30°C constant-temperature chamber or beside a stove for germination, and generally after 48 hours they can all germinate.

4. Open-field sowing. When the sprouts are 1—2 fen long, they can be selected for sowing, sowing 2—3 seeds per hole, with the sprout tip pointing downward, covering with soil about 2—3 cm thick, and watering the root-setting water immediately after sowing; if it is sunny, water should still be given once on the 2nd—3rd day. When the seedlings have 2—3 true leaves, thin them to a stand, removing the thinner plant from any double-plant hills, and promptly filling in gaps where seedlings are missing.

5. Insulated seedling raising. Raising seedlings in nutrient pots plus plastic film covering requires meticulous work, and the following key links should be handled well. ① Making the nutrient pots. The pot body can be made from old newspaper or book paper into a paper tube 20 cm long, 13 cm wide, 8—10 cm high, and 6 cm in diameter. ② Preparing the nutrient soil. Use 60—70% garden soil that has not grown cucurbits in recent years, add 10—15% sieved coal ash or burnt soil ash, add 20—25% decomposed pig or cattle manure and 0.2% phosphate fertilizer, mix thoroughly; more than 300 jin should be prepared per mu, and after preparation it should be piled, covered and sealed for later use. ③ Management and transplanting of film-raised seedlings. After true leaves appear, pay attention to ventilating the seedbed, letting in light and regulating temperature and humidity, to prevent the occurrence and harm of damping-off, anthracnose and Rhizoctonia rot. When the melon seedlings have two leaves, choose good weather to harden the seedlings and remove the film; when the melon seedlings have two leaves and one heart or three leaves and one heart, and the outside temperature is stable at 15°C, they can be transplanted to the field in time.

II. Reasonable close planting and good fertilizer management

1. The planting density of watermelon varies with variety and soil fertility, and about 450 plants per mu is suitable. For varieties with medium vigor, about 500 plants is suitable. That is, with the trench included, the bed width is 9 chi, planting one row along each side of the bed, with a plant spacing (hill spacing) of 2.6 chi.

2. Cultivate and loosen the soil and remove weeds in time; generally 2—3 cultivations are needed, and in topdressing, the principle of small meals and frequent meals, light first and heavy later, should be grasped.

3. Seedling-promoting fertilizer: it can be applied once the melon seedlings have settled and show true leaves, applied once every 10—15 days, each time 15—20 dan per mu (each dan contains 10% decomposed human and animal manure, plus 1 liang of urea, and 100 jin of water); on rainy days, 3—5 jin of urea per mu can be applied in holes 2—3 cun from the roots.

4. Vine-spreading fertilizer: apply when the melon seedlings have 5—6 leaves, using 100—200 jin of decomposed cake fertilizer and 10—20 dan of human and animal manure per mu, applied in holes opened one chi from the hill in the direction the vines extend.

5. Fruit-fattening fertilizer: when 60—70% of the melons are as big as eggs, apply 100—200 jin of cake fertilizer and 15—20 dan of human and animal manure per mu in holes.

First-melon fertilizer: when most melons are as big as a bowl, apply 15—20 jin of urea plus 5—8 jin of potash fertilizer per mu, mixed with water, near the melon hills.

6. Second-melon fertilizer: after the first batch of melons is picked, in order to grow the second and third batches of melons well and prevent premature aging of the vines, apply 20—26 jin of urea per mu.

III. Adopt multiple measures to increase the fruit-setting rate

1. Pruning and removing superfluous shoots: pruning methods include single-vine, two-vine and three-vine types. The single-vine type keeps the main vine and removes the side branches on the main vine; this method results in fewer leaves per plant and smaller fruit shape, and is generally only suitable for high-density situations. The two-vine or three-vine type removes the side branches sprouting from the leaf axils of the 3rd—7th nodes at the base of the plant, keeping only 1—2 branches that grow vigorously and in a suitable direction. Pruning work should be done in stages, mainly in the early stage of vegetative growth and the early fruiting stage; the first pruning should be done when the 2nd—3rd female flowers on the main vine open and several relatively vigorous side branches have formed around the node positions of the female flowers; the side branches should be removed in time, and when the fruit set on the main vine is as big as an egg, pruning should stop. Removing superfluous shoots should be carried out from fruit setting until before the whole field of watermelons is harvested, wiping out excess shoots, reducing tender leaves and small leaves, retaining large and strong leaves, concentrating nutrients, and promoting fruit development.

2. Pressing and arranging vines: vine-pressing method: when the melon vine grows longer than 1 chi and starts to fall over, press a clod of soil in the direction opposite to the extension of the main vine, making the main vine tilt forward; to prevent damage from wind and rain, press once every 4—5 nodes thereafter. Vine-arranging method: when the main vine extends, straighten and evenly arrange the vines; afterward, it is enough just to set the position of the growing point correctly; generally arranging 3—4 times and pressing 3—4 times is sufficient.

3. Artificial supplementary pollination. The method is: in the early morning, pick male flower buds that will open that day and place them in a small basin to let them open naturally; after the female flowers open, peel off the petals of the male flowers and smear the twisted anthers onto the honeycomb-like stigma of the female flowers; each male flower can pollinate 1—2 female flowers. But care should be taken not to touch the ovary, so as to avoid damaging it. Pollination is generally carried out before 9 a.m. When field plants grow uniformly, the node positions at which female flowers open are relatively uniform, and generally one wave of flowers is 5—6 days apart; therefore, artificial pollination does not need to be done every day, and it is enough to select the ideal fruit-setting position and carry it out for 2—3 days at full bloom.

4. Selecting and keeping melons. Generally it is suitable to keep the melon set by the 2nd—3rd female flower on the main vine; without pruning, sometimes several melons set on one plant, and the fruit shape is markedly reduced; poorly shaped young fruits can be removed, keeping 1—2, concentrating nutrients and enlarging the fruit shape.

5. Using hormones. Spraying flower-and-fruit-preserving king can markedly increase the fruit-setting rate, but it must not adhere to young fruits.

To grow watermelon for high yield, one can never do without practice and the accumulation of experience. The above are the technical key points for high-yield watermelon compiled by Qinnong Net based on the experience of others for everyone; when applying them specifically, fruit growers can combine their own experience and the local climate and environment, adapt measures to local conditions, and invent their own high-yield techniques.