PURPOSE: To make even the water supply capacity to a banking irrespectively of the location by providing a recess part for keeping water in each adjoining base member for planting, communicating each other through communication holes, and thereby making even the water keeping quantities of different base members.

CONSTITUTION: Recesses part 11, 11 for keeping water are formed in the central part of each base member for planting 10, and the peripheral walls 14 are equipped with a coupling structure for adjacent bases for planting 10 and also communication holes to put the recesses 11 of the adjoining bases in communication to each other when coupling is generated. Then a plurality of such bases 10 are coupled together, where the communication holes of those bases 10 at the peripheries are blocked, provided that part thereof is/are arranged as capable of being opened. Water is supplied concentratedly to the recess 11 of at least one of bases 10. The water supplied flows farther to the recesses 11 of adjoining bases 10, and the water supply ability to the banking is made even irrespective of the location. If part of the blocked communication hole(s) at the periphery is/are opened, drainage from the whole area is made which enables easy replacement of the stagnating water.