A method for producing a plant seedling is provided, which is based on microwave radiation in order to efficiently facilitate the plant growth. In the method, microwave radiation is started at any timing during a period ranging from appearance of a first true leaf to a timing provided before appearance of a second true leaf in a growth process of a plant. The radiation time of the microwave may he within 1 hour, and the output of the microwave may be 2 to 25 W per 1 to 20 seedling or seedlings.
