To promote the germination of a gel coated seed without adding a new process to prolong a period from the production of the gel coated seed to the sowing without requiring excessive labor or cost.

A gel coated seed 3 obtained by coating a seed 33 with gel 31 which is formed by hardening a coating agent, is raised. In this case, in the state of sowing the gel coated seed 3 over a culture medium inside a tray 1 opened upward, the gel coated seed 3 is immersed in water or low-osmotic pressure solution W at the water level reaching the gel 31 at least, and the gel 31 is swelled and exploded by absorbing the water or low-osmotic pressure solution W. Next, the moisture of water or low-osmotic pressure solution W contained in the culture medium is adjusted to a prescribed quantity suitable for the germination of the seed 33, and the seed 33 is germinated by the water or by the low-osmotic pressure solution W absorbed by the seed 33 from the culture medium.