A plant growing method, including the steps of: planting the plant (16) in a first compartment (70) of a planter (10); allowing roots (18) of the plant (16) to grow from the first compartment (70) into a second compartment (72A) of the of planter (10), while the first (70) and second (72A) compartments are not partitioned; cutting horizontally the grown roots (18) by partitioning (22) the first compartment (70) from the second compartment (72A) by a saw (52), disposed at the bottom of a vertical partition (20A); and removing the cut roots (18) from the second compartment (72A), thereby allowing the cut roots (18) to further grow from the first compartment (70) into the second compartment (72A).L'invention concerne un procédé de culture de plantes, comprenant les étapes consistant à : planter la plante (16) dans un premier compartiment (70) d'un bac à fleurs (10) ; laisser les racines (18) de la plante (16) pousser depuis le premier compartiment (70) vers un second compartiment (72A) du bac à fleurs (10), pendant que les premier (70) et second (72A) compartiments ne sont pas séparés ; couper horizontalement les racines ayant poussé (18) en séparant (22) le premier compartiment (70) et le second compartiment (72A) par une scie (52), disposée au fond d'une cloison verticale (20A) ; et retirer les racines coupées (18) du second compartiment (72A), ce qui permet que les racines coupées (18) poussent encore depuis le premier compartiment (70) vers le second compartiment (72A).