To solve problems that the realization of a reduction in weight is more difficult in the building wall surfaces than that on the rooftop, the water sprinkling on wall surfaces is difficult, windbreaking techniques and maintenance and control after planting cannot readily be carried out, plants such as ivies have roots (sucking roots) such as suckers and promote aging of buildings, etc., are cited as one of reasons in delayed wall surface greening as countermeasures for urban greening for eliminating heat islanding phenomenon.

This piping hydroponic system for greening the building wall surfaces is designed so that a culture solution 4 for hydroponics drawn up from a lower water storage tank 2 with a storage pump 1 flows through a circulating pipe 3 and plants 7 absorbing nutrients from a planting foundation material 6 in each trough plant growth pipe 8 exchangeable from an upper water storage tank 5 on the building are prevented from growing roots of the plants 7 and blocking a water channel with a root-proofing net 10 on a reticulated trestle in the pipe 8 and both ends 12 of the trough plant growth pipe 8 are connected to cylindrical pipes to circulate the culture solution 4.