PROBLEM TO BE SOLVED: To provide a tomato seedling raising method, a seedling raising apparatus and a plant factory which are capable of suppressing onset of viral diseases, safe, and excellent in economical efficiency.SOLUTION: The tomato seedling raising method of the present invention comprises a step of irradiating tomato seedlings with light by using LED light sources, where the LED light sources used in the step include a wavelength region of 280 nm or more and 290 nm or less and about light to be irradiated to tomato seedlings, an irradiation amount of a wavelength component of 280 nm or more and 290 nm or less is 0.7 kJ/mor more and 1.4 kJ/mor less per day. The tomato seedling raising method of the present invention can be easily performed by installing LED light sources in a seedling raising apparatus and in a plant factory, the LED light sources being capable of irradiating tomato seedlings with light of a wavelength region of 280 nm or more and 290 nm or less in an irradiation amount of 0.7 kJ/mor more and 1.4 kJ/mor less per day.【課題】ウイルス病の発病を抑制可能な、安全で経済性に優れるトマト育苗方法、育苗装置及び植物工場を提供する。【解決手段】本発明のトマト育苗方法は、ＬＥＤ光源を用いてトマト苗に光を照射する工程を有し、当該工程で使用するＬＥＤ光源は、２８０ｎｍ以上２９０ｎｍ以下の波長域を含み、トマト苗に照射する光は、２８０ｎｍ以上２９０ｎｍ以下の波長成分の照射量が１日当たり０．７ｋＪ／ｍ２以上１．４ｋＪ／ｍ２以下である。また育苗装置及び植物工場に２８０ｎｍ以上２９０ｎｍ以下の波長域の光を、１日当たり０．７ｋＪ／ｍ２以上１．４ｋＪ／ｍ２以下の照射量でトマト苗に照射可能なＬＥＤ光源を設置することで、本発明のトマト育苗方法を容易に実施することができる。【選択図】図７
