It is intended to provide an apparatus for producing seedlings and a method therefor whereby, in producing grafted seedlings of fruit vegetables, a process from the culture of their stocks (rootstocks and scions) to welding after the grafting can be accomplished in a consistent process at low cost. Rootstocks and scions are nursed on multi-staged seedling culture shelves 3 installed in a closed-type structure surrounded by light-interceptive thermally insulating walls, and then these rootstocks and scions are joined to each other to produce grafted seedlings 8. Then, these grafted seedlings 8 are placed on shelf boards 3a of the seedling culture shelves and covered with a light-transmitting shield 9 provided with vent holes 15, and light of a predetermined luminous intensity is projected onto these grafted seedlings from fluorescent lamps 5 through the light-transmitting shield to weld the grafted seedlings 8. The relative humidity in the light-transmitting shield immediately after the grafting is raised by the evaporation of moisture from the rootstocks and the scions, and the rooting of the rootstocks and the scions is thereby facilitated. When the photosynthesis is stimulated, gas exchange between the carbon dioxide gas-containing atmosphere within the closed type structure and the atmosphere within the light-transmitting shield are accomplished to replenish the inner space of the light-transmitting shield with carbon dioxide gas.
