To solve a problem such that since it is necessary to have a wide ridge distance for planting seedlings as a laid down posture in a conventional ridge furrowing method, it is difficult to perform crowded cultivation for improving its yield per unit area, to improve the yield per unit area widely, also to enable a bag type or frame type cultivation and to make the agriculture as a light work or as an industry.

This method for cultivating welsh onion is provided by fixing seedlings of the onion on a belt-shaped material having some stiffness, e.g. a thin belt-shaped foamed styrene plate at right angle to a longitudinal direction by taking a suitable interval, planting the seedling in a standing state and giving a material for holding soil along planted rows to shorten the ridge distance for enabling the crowded cultivation.