When and How to Transplant Early-Maturing Black Beauty Melon Seedlings and Post-Transplant Management to Prevent Seedling Death

Black Beauty melon is one of the sweeter melons among the melon family and is cultivated in most parts of our country, but to achieve high yields, you need to raise good seedlings and carry out basic management work. So when is the best time to transplant Black Beauty melon seedlings? How do you transplant them? How do you prevent seedling death? How do you manage them after transplanting?

Transplanting time:

The suitable age for normal transplanting is the four-leaf stage. When seedlings are small, because their growth amount is small and their adaptability and resistance to the outside world are poor, they recover slowly from transplanting. But large seedlings with five leaves or more will cause adverse results such as root damage, corking of the outer epidermis of the underground stem, and hollowing of the pith. 5~7 days before planting, hardening off can begin, extending the daytime ventilation time so that the seedbed temperature gradually decreases, which can promote rooting, enhance the cold resistance and disease resistance of the melon seedlings, and increase the survival rate of the melon seedlings after transplanting. 1~2 days before transplanting, you can spray a 800-fold dilution of Weibu Guoli, together with a fungicide, to prevent leaf rot, promote strong seedlings, and improve cold resistance.

Transplanting method:

1. Before transplanting the melon seedlings, in order to allow the seedlings raised under protected conditions to adapt to the field environment, about one week before the planned planting, the melon seedlings need to be treated with cooling and water control, that is, hardening off, which promotes the aging of watermelon seedling tissues and improves adaptability and stress resistance.

2. Black Beauty watermelon seedlings should be transplanted in the morning on a run of consecutive fine days, to raise the soil temperature as much as possible and prompt the melon seedlings to quickly grow new roots and recover and survive. If seedlings are planted in low-temperature weather or encounter continuous low-temperature weather after planting, it is easy to cause root suffocation or stiff seedlings in Black Beauty watermelon. Generally, planting can be done when the soil temperature at 10 cm reaches above 15°C.

3. The planting depth of melon seedlings should be such that the surface of the nutrient soil is buried about 1 cm into the soil. Too deep and the soil warms up slowly and has poor aeration; too shallow and it is difficult to retain moisture. Both of these affect the root development of Black Beauty watermelon and cause slow watermelon growth. When planting grafted seedlings, the graft union must be at least 1~2 cm above the ground. Planting too deep causes the hypocotyl part of the Black Beauty watermelon (scion) to contact the soil and produce its own roots, making grafting meaningless.

4. One day before planting the seedlings, water thoroughly once to prevent the nutrient soil blocks from breaking apart during planting and causing Black Beauty watermelon seedling death. At the same time, spray the seedbed once with a mixture of 79% thiophanate-methyl wettable powder at 800-fold dilution and 40% dimethoate emulsifiable concentrate to prevent pests and diseases, saving the trouble of spraying again after transplanting to the field.

Methods to avoid seedling death:

1. Do not transplant when the temperature is low. After transplanting Black Beauty watermelon, the underground temperature should be around 15°C. For melon seedlings transplanted in early spring, if the soil temperature at 10 cm underground does not reach 15°C, they cannot develop roots. Therefore, using mulching in advance to raise the soil temperature before transplanting will greatly increase the survival rate.

2. The soil manure used as base fertilizer must be mixed evenly with soil. After transplanting Black Beauty watermelon, if the roots contact organic fertilizer or chemical fertilizer with too high a concentration, “root burn” will occur, which will cause seedling death. Therefore, the base fertilizer must be thoroughly and evenly mixed with the soil.

3. Small seedlings should not be transplanted. The suitable period for watermelon transplanting is the four-leaf stage, generally when the seedling age is about 28 days. If the seedlings are too small, their adaptability and resistance to the outside world will be poor, and their growth capacity will be insufficient, which will lead to slow recovery after transplanting.

4. Harden off properly. Before transplanting the melon seedlings, one week before planting, treat the melon seedlings with cooling and water control, that is, hardening off. Hardening off promotes the aging of watermelon seedling tissues to improve the adaptability and stress resistance of the seedlings.

5. Eliminate inferior seedlings and select seedlings that are relatively well developed, discarding diseased, weak, small, and other poor seedlings.

6. The seedbed should not lack water, and watering should be moderate. Before transplanting, control the temperature of the seedbed but not the water, to maintain the health and integrity of the root system. After transplanting, while maintaining the soil temperature, watering should firmly settle the seedbed soil.

7. Pay attention to soil treatment. Because there are large numbers of pests and pathogens in the soil, as the underground temperature gradually rises, the occurrence period of pests and diseases will also advance. If the control of soil pests and diseases is neglected, serious consequences will result. Therefore, it is very necessary to use a certain amount of fungicide to sterilize the soil, so as to ensure normal and healthy growth of watermelon after transplanting.

8. Do not fertilize or water too early. When promoting watermelon seedling growth, the amount of topdressing and watering should be decided according to the growth status of the melon seedlings and the fertility of the soil. Providing water and fertilizer too early is harmful, and more can be applied after Black Beauty watermelon is transplanted.

Post-transplant management techniques:

1. Water and fertilizer work

In the early growth stage of Black Beauty watermelon, attention should mainly be paid to the application of nitrogen fertilizer, and a small amount of potassium fertilizer and phosphorus fertilizer should also be used, in order to promote the rapid growth of the vines. During the flowering period, the application of nitrogen fertilizer should be appropriately reduced and the application amounts of phosphorus fertilizer and potassium fertilizer increased, in order to increase the fruit-setting rate of the plants. After the plants have set watermelon fruit, the application amount of nitrogen fertilizer should be increased again, in order to rapidly promote watermelon growth. Finally, in the early stage of fruit ripening, attention should be paid to increasing the amount of potassium fertilizer to improve the quality of the fruit. Throughout the entire growth cycle of Black Beauty watermelon, the most suitable amount of compound fertilizer applied per mu is about 20 kg, urea 15 kg, and calcium phosphate about 40 kg.

Throughout the entire growth cycle of Black Beauty watermelon, care should be taken to keep the soil moisture sufficient. When the vines are extending, the soil should be kept moist. After fruit set, ensure that the plant's growing environment has sufficient water available for absorption. However, attention should be paid to drainage, especially the large amount of rainfall caused by typhoons. During the growth cycle, watermelons must not be soaked in water.

2. Vine and branch management work

When Black Beauty watermelon begins to run vines, pinching should be carried out. Each main vine should retain three or four side vines, with the retention principle being that the side vines grow robustly. After fruit set, some of the non-fruiting side vines should be removed, while appropriately retaining some, mainly to ensure the nutrient supply needed for watermelon growth.

3. Pollination and fruit retention work

Pollination of Black Beauty watermelon generally uses artificial pollination. In artificial pollination, varieties with similar flowering periods to the breeding line should be ensured as pollinating plants. The specific method is: pollination is carried out at around ten o'clock at noon, and during pollination there should be no watering or fertilizing work, so as not to affect the fruit-setting rate of the watermelon. When the female flowers are in full bloom, when the stigma has the most mucus, collect opened male flowers and carry out thorough pollination work. Ensure the entire stigma is covered with pollen, to increase the fruit-setting rate of the plants.

Regarding the issue of fruit retention in Black Beauty watermelon, we first need to know that the watermelon set by the first female flower on the main vine is not of very good quality: the fruit shape is flat, the rind is thicker, and it is prone to hollow heart, so it should not be retained. The watermelons set by the second and third female flowers on the main vine, as well as those from well-developed side vines, should be retained. The principle is to observe the development of the vines; generally, watermelons on vines with good development should be retained.