Key Points of Transplanting Techniques for Muskmelon Cultivation in Small Tunnels

① Transplanting Timing The transplanting timing is an important factor determining early maturity and high yield. Transplanting too early makes it difficult for seedlings to survive due to low soil temperature; transplanting too late fails to achieve the goal of early maturity. The earliest transplanting time should be when the local average daily temperature rises to 10°C and the average daily temperature under the plastic film on the high ridge at a depth of 10 cm reaches above 18°C. It is advisable to choose clear, warm and windless weather for transplanting, and immediately cover with the tunnel film for insulation after transplanting.

② Transplanting Method For single-row cultivation on high ridges, transplant seedlings at a spacing of 35-40 cm in the center of the ridge, slightly toward the south. According to observations, the center of an east-west oriented high ridge, slightly toward the south, is where the soil temperature is highest, so seedlings should be planted there. When vines begin to trail, they can be directed in one direction along the wind, making it less likely for the vines to be blown over. The advantage of single-row cultivation is that seedlings are transplanted in the middle of the ridge surface, and the seedlings remain inside the arched tunnel for a relatively long time, maximizing the warming effect of the small arched tunnel. Therefore, single-row cultivation is adopted in three-film covering and three-film plus straw mat small arched tunnel cultivation, with 900-1,000 seedlings planted per 667 sq m.

③ Transplanting Method The upright planting method is the commonly used transplanting method. Place strong seedlings that have been hardened by low temperatures along one side of the ridge, then lift one side of the small arched tunnel and punch holes along the ridge at the appropriate spacing for transplanting. To prevent the soil temperature from dropping too quickly, water is applied into each hole at transplanting; the transplanting depth should be such that the top of the soil ball is level with the ridge surface, fill with moist soil around it, seal the transplanting opening tightly, and cover the small arched tunnel as you go. Another method is the sun-facing pit transplanting method. After the high ridge is prepared, dig small pits (sun-facing pits) along the ridge at the appropriate spacing, facing south with a diameter of about 15 cm and a depth of about 10 cm, and cover with plastic film to raise soil temperature; at transplanting, first uncover the plastic film, open a hole on the north side of the sun-facing pit, place the soil-ball seedling with roots facing north and the shoot tip facing south, bury the roots in the newly opened hole, and lay the seedling flat in the pre-dug sun-facing pit. After planting a row, cover with plastic film to retain heat and moisture. Finally, cut an egg-sized hole in the plastic film directly above the seedling for ventilation and gas exchange to prevent leggy growth, then set up the arched frame and cover with the arched tunnel. After 3-5 days of transplanting, pull the seedlings out through the holes in the plastic film so that the aboveground parts of the seedlings grow above the plastic film and below the tunnel film. This form keeps the seedlings in the recovery period under the double covering of the small tunnel and plastic film, providing good insulation, and allows transplanting 5-7 days earlier than ordinary double-film covering.