培植土可以反覆使用。當培植土底部被植物根部破壞太多時才需要換。正常水生植物的根部對比土種植物來說是非常幼細。如是芽類植物，每次收成之後把舊種子及幼根清除便可以重新播種及使用。如果是蔬菜類植物，每次收成後便因根部太多不能清除而不能改種其他植物而要更換。當種植觀賞類植物，如果不改種新植物也可繼續使用，否則便需要更換。The growing medium provided with Potti is designed for repeat usage until it has been deformed and damaged by the root. Plants that grown in aqua-culture has comparatively smaller root.If you grow sprouts type of green, which can be easily removed and plant new seeds. For leafy salad type of plants, it is advised to change as the growing medium will be deformed.
As for ornamental plants, change of growing medium is not necessary until a new type of plant is introduced.