The container (1) has an upper opening (10) surrounded by an upper edge (11) and sealed by a cover, where the cover has a slackened, flask and/or slightly concave shape. A triangular/trapezoidal shaped circumferential protuberance (12) is made of fusible material having a melting point lower than melting point of the cover on the upper edge around the upper opening. The circumferential protuberance is located at an internal border of the upper edge delimiting the upper opening and secured to the container during molding of the container. An independent claim is also included for a method for forming and sealing a horticultural container.Linvention concerne un contenant horticole (1) présentant une ouverture supérieure (10) entourée dun rebord supérieur (11) et apte à être operculée par un opercule (2), caractérisé en ce que le contenant (1) intègre une protubérance circonférentielle (12) en matière fusible de température de fusion inférieure à la température de fusion de lopercule (2) sur son rebord supérieur (11) autour de son ouverture supérieure (10).
