Detailed Cultivation Techniques for Mini Watermelons in Summer and Autumn

For summer-autumn watermelons, especially mini watermelons, the quality is excellent, the price is high, the benefits are good, and the market prospects are broad. The relevant practical experience is summarized as follows. 

Variety selection: Summer-autumn watermelon varieties must be able to tolerate high temperature and heavy rain, show stable fruit setting under high temperature conditions, and achieve relatively high sugar content in an environment with a small temperature difference between day and night. Better varieties: Black Beauty, Xiaoling, Liling, Xiaolan, Diana.   Determining the sowing period: Sow in mid-May, set fruit after the plum rain ends, and harvest before the typhoon arrives. Sowing during this period is more suitable for open-field cultivation, with lower risk and lower cost. When sowing from late June to early July, the early stage is not affected by the plum rain, but it is easily affected by typhoons in August, so rain-shelter facility cultivation should be used. This period can be marketed in mid-September, when the watermelon market conditions are relatively good.   Soil preparation: Continuous cropping land should be avoided as much as possible. If land previously used for watermelons or muskmelons must be used for continuous cropping, then immediately after the previous crop is harvested, pour 500-fold formaldehyde solution onto the bed surface to disinfect the soil. In addition, too low soil pH can easily cause fusarium wilt, so for fields that are too acidic, quicklime can be spread on the bed surface to neutralize it. Summer-autumn watermelons have a short growth period and very high requirements for soil and fertilizer. Generally, base fertilizer is mainly organic fertilizer, with 500 kg of decomposed organic fertilizer, 40 kg of potassium sulfate compound fertilizer, 30 kg of superphosphate, and 0.5 kg of borax applied per mu.   Sowing: Select seeds and soak them in 55-degree warm water while stirring. After the temperature drops to room temperature, continue soaking for 4 to 6 hours, then germinate them in a 30-degree environment. Generally, germination takes 24 hours, and once the seeds show white, they can be sown. Before sowing, first pour sterilized water thoroughly into the planting holes, then place the seeds that have shown white into the holes, paying attention to keep the sprout tip facing downward. Generally, place 1 seed in a hole if it has germinated, and 2 seeds if it has not. After sowing, cover with a layer of fine soil, then use a sprayer to soak the covering soil thoroughly so that it fits closely with the seeds. Sowing should be done in the evening or on cloudy days, so that the seeds can germinate in a short time and avoid dehydration and seedling death caused by exposure to the sun.   Field management: Transplanting: Make beds 2.8 m wide including trenches, plant 15 rows per bed, with a plant spacing of 0.5 m, planting 400 to 540 plants per mu. Fertilization: One week after transplanting, apply a survival fertilizer, mainly nitrogen fertilizer, to promote the growth of side vines, mainly by watering the planting holes. One week after survival, apply compound fertilizer to promote vine extension. When the fruit is the size of an egg, apply a fruit-swelling fertilizer, which can be applied into the furrows together with field irrigation. In the later stage of fruit development, when plants grow slowly and show premature senescence due to excessively high temperatures, nutrient solution fertilizer or potassium dihydrogen phosphate can be sprayed on the leaves. Pruning: All vines that appear before the fruit-setting position need to be removed; vines that appear before the fruit-setting position should be sprayed. Pruning: Vines that appear before the fruit-setting position can be allowed to grow freely as nutrient vines. Pruning is mainly based on the three or four vines of the main vine. For mini watermelons, keep 3 to 4 fruits per plant; for medium-sized melons, keep 1 to 2.   Artificial pollination: To increase the fruit-setting rate, artificial pollination must be carried out. Mini watermelons mature about 25 days after pollination, and medium-sized watermelons mature about 28 days after pollination. Pest and disease control: Pest and disease control is the same as for general spring watermelons, but summer-autumn cropping occurs in the high-temperature and rainy season, when anthracnose is severe, so a prevention-oriented policy should be adopted. After entering the fruit-setting period, apply chemicals once a week for control, and during continuous heavy rain, spray to supplement control after each heavy rain.