Some Findings in Spinach Plug Seedling Transplanting Cultivation After Introduction of an Electric Semi-Automatic Transplanter

To establish a plug seedling transplant cultivation system for spinach using an electric semi-automatic transplanter, the results of cultivation was examined. Stable spinach production in summer was possible, and the growing period of spinach after transplanting in the field (where it was protected by a plastic film greenhouse) compared with that of direct sowing cultivation was shortened up to 70% in late autumn, and 50% in winter. Yield and externals when harvesting were decreased by transplanting plug seedlings shallowly. Decrease in the proper transplant rate because of differences in the harrowing ratio was entirely due to the generation of shallowly transplanted plants. Decrease in the transplant accuracy was able to be prevented by plowing clods to less than 9.5mm in diameter. The pulling out success rate was increased because of an increase in water content of the rootball by subirrigating seedlings before transplanting. The rootball formation rate and the pulling out success rate were increased by double seed sowing.