The invention relates to a method of manufacturing a culture medium on which plants can be grown. This method is characterized by a) mixing I: a particulate base material, chosen from at least one of organic and inorganic materials, with II: a thermoplastic biologically degradable binding agent, b) heating at least the binding agent in order to at least partly fluidize it, c) cooling the mixture so as to substantially solidify the binding agent and whereby at least a part of the base material becomes bonded by means of the binding agent. The method according to the invention provides an environmentally safe and plant-friendly culture medium that is biologically degradable and retains its shape well.