The present invention relates to a modular container system for use in agriculture, gardening and construction, characterized in that it comprises a parallelepiped container 1 with two partition walls 2 forming three chambers 3, its top ends each having a sleeve 4 which forms a vertical channel 5, the lower end 6 of the said sleeve extending beyond the bottom of the container but with slightly smaller dimensions and having a groove 10 around its whole periphery; connectors 9 which join adjacent containers in a horizontal plane; a base 11 which allows the containers to rest on the ground; and a lateral support 13 exactly identical to the top end of the container 1.