When and how should watermelon be grafted for a high survival rate?
Grafting is one of the methods of artificial propagation of plants, with effects such as earlier fruiting, drought resistance and cold resistance. Below, taking watermelon as an example, let us learn about when watermelon should be grafted and what method gives a high survival rate.
When should watermelon be grafted?
1. When grafting watermelon by the insert method, it is best to do it at the stage when the first true leaf has unfolded, and the grafting period can last 8-10 days.
2. For others, it is preferable to carry them out in spring and autumn. During grafting, attention should be paid to keeping warm, retaining moisture and shading, so as to ensure the survival rate.
What method should be used to graft watermelon for a high survival rate?
1. Insert grafting method
During grafting, the best time is when the first true leaf of the rootstock has unfolded. The grafting time is 6-8 days after the rootstock emerges, and the grafting period can last 8-10 days. For watermelon scions, it is best when the cotyledons have just unfolded. Before grafting, first prepare a bamboo skewer, with a thickness equal to or slightly thicker than the watermelon seedling, and cut the front end into a wedge-shaped surface. During grafting, first remove the growing point of the rootstock seedling, then use the flat and wide tip of the bamboo skewer, in a direction parallel to the cotyledons, to insert diagonally downward from the growing point to a depth of about 1 cm, so that the tip of the bamboo skewer just emerges from the rootstock. Then take the scion and use a blade to cut a wedge-shaped surface about 1 cm long at 1 cm below the cotyledons, pull out the bamboo skewer, insert the cut end of the scion into the hole, with the tip slightly emerging from the rootstock. Spraying the scion cut promptly with new high lipid film can prevent oxidation, prevent the invasion of pathogens and improve the survival rate.
2. Approach grafting method
Pull the scion out from the seedling tray. At 1 cm below the leaves of the rootstock seedling, use a blade to cut diagonally from top to bottom a 1 cm incision, with the incision depth reaching 95% of the diameter of the rootstock hypocotyl. On the scion, at 2 cm below the cotyledons, cut diagonally from top to bottom an incision about 1 cm long, then fit the two together in a tongue shape, tie them with plastic strips or clamp them with a grafting clip, then dig a small hole in the rootstock's nutrient pot, bury the scion in the soil and water it. For grafted cultivation of watermelon, gourd can be selected as the rootstock. When using the approach grafting method, the rootstock and scion are sown at the same time.
Seedbed management
After grafting, the seedbed must be managed intensively to achieve the best survival rate: keep warm. The suitable temperature for the healing of grafted seedlings is 20-28°C. The seedbed temperature must be checked frequently, keeping the temperature at noon during the day no higher than 28°C and at night no lower than 20°C. Keep moist. Before the grafted seedlings heal, the scions cannot obtain water absorbed by the root system of the rootstock, and the scions are very prone to wilting. Therefore, within 3 days after grafting, the relative air humidity should be maintained at 100%, that is, after grafting, water the ground thoroughly to keep water droplets on the film surface. Only after 3 days can ventilation be gradually started, ventilating 1-2 times a day, in the early morning and evening. After 1 week, the greenhouse film can be opened a little to ventilate and lower the temperature. Shade. Within 2 days after grafting, strictly shade; after 2 days, strong light can be shaded, and light can be gradually increased; only after 1 week is shading no longer needed. Pay attention to water control. Watermelon likes dry conditions and is not tolerant of moisture. During the seedling stage, generally do not water or apply additional fertilizer. If the seedbed is too dry, a small amount of water can be given at noon on a sunny day. When fertilizer is lacking, spray urea + photosynthetic nutrient film fertilizer on the leaves to improve the absorption of fertilizer efficiency.
When grafting watermelon, it is recommended to do it in a greenhouse. Only when temperature and humidity are ensured will the survival rate be high.