Detailed Explanation of Key Techniques for Open-Field Watermelon Cultivation

Watermelon flesh is sweet and is a fruit that many people love to eat. Eating it in summer can cool you down and relieve the heat, and its cultivation history in our country is long. Below, the editor will introduce open-field watermelon cultivation techniques.

1. Site selection and land preparation

It is advisable to choose sandy loam with deep soil layers, loose and fertile soil, and convenient drainage and irrigation, and to cultivate on plots where no cucurbit crops have been grown within 5 years for dry land and within 3 years for paddy fields. After selecting the land, plow deeply and apply sufficient base fertilizer, and adopt raised-bed planting, with wide beds 4-4.5 m and narrow beds 2.0-2.5 m. On wide beds, plants can be set on both sides of the bed with vines climbing toward each other, or set in the middle with vines climbing to both sides; on narrow beds, plants are set on one side with vines climbing to one side.

2. Sowing and seedling raising

Seed soaking and germination promotion: first soak watermelon seeds in 0.4% formalin for 1 hour, remove them and rinse with clean water, then soak in clean water for 8-10 hours and remove them, rub off the mucus on the seed coat with a towel, wrap them in a damp cloth, put them in a plastic bag, and place the bag in a person's inner clothing pocket to promote germination using body temperature. After 12 hours, drench the seeds once with warm water. Generally after 24-36 hours, most seeds will show white and can be sown.

3. Transplanting

Early-maturing watermelon seedlings are about 1 month old and can be transplanted once they grow 2-3 true leaves. Mid-maturing watermelon seedlings can be transplanted at 20-25 days old, and late-maturing watermelon seedlings at 7-10 days old. Set 2 rows on wide beds and 1 row on narrow beds.

4. Pruning and vine pressing

Generally, the three-vine pruning method is used. When the main vine has 8-9 leaves, keep the main vine and two robust side vines, and remove all other secondary and tertiary vines. Pruning should not be done on rainy days to prevent the spread of disease. When the vines grow to about 50 cm, press the vines with soil together with pruning, then press once more at an interval of 3-4 nodes, for a total of 2-3 pressings per vine, and arrange the vines evenly.

5. Water and fertilizer

When the young fruit grows to the size of an egg, apply fruit-swelling fertilizer according to the plant growth condition, generally applying 15-20 kg per mu of 45% nitro-sulfur-based or potassium sulfate-type controlled-release fertilizer. During the seedling stage, water as little as possible, or even do not water, to promote the formation of a well-developed root system in the seedlings; control moisture before flowering and fruit set to prevent excessive growth; after fruit set, ensure sufficient water supply to facilitate fruit enlargement and increase weight. Do not water in the 7-10 days before harvest, so that the fruit accumulates sugar. When water is lacking, irrigate in the early morning or at night when temperatures are lower. Use furrow irrigation and seepage, that is, irrigate into the bed furrow, and once the water has seeped into the melon ridge, immediately drain the remaining water in the furrow. After irrigation and rain, immediately drain the accumulated water in the field, otherwise it is easy to cause root rot and vine rot.

6. Harvest

Generally, early-maturing varieties are harvested about 30 days after pollination, mid-maturing varieties about 35 days, and late-maturing varieties about 40 days. The speed of fruit ripening is affected by temperature, light intensity, and time. It is best to note the date at pollination, and when maturity is expected, take a sample melon, cut the fruit open, measure its sugar content and taste it, and after confirming maturity, harvest in batches according to the markers.