PROBLEM TO BE SOLVED: To provide in a system for heating a shallow layer in a protected horticulture greenhouse, water-sealing tube which reduces heating equipment cost and operation cost and maintains the lower limit temperature of clop plants, and a method of using the same.SOLUTION: Provided is a system for heating a shallow earth layer, in which a heat collecting and accumulating bag 3, which is high in absorptivity of sunlight energy and to undersurface of which a heat insulation layer 30 is arranged, is accommodated in a plastic resin transparent bag 2, which is high in transmittance of sunlight energy and forms an air layer a having sunlight transmitting, thermal insulation characteristics； and a solar light collecting and accumulating bag body 1 for thermal conduction to a heat storage medium W in the heat collecting and accumulating bag 3, is installed extending on a plow layer 50, so that the plow layer 50 is moderately heated and stored the heat.【課題】施設園芸ハウスの浅層加温システムにおいて、暖房設備費及び運転費の削減を実施し、作物の下限温度を維持する水封チューブ及び使用方法を提供する。【解決手段】太陽光エネルギーの透過率が高く、透過断熱性の空気層ａを形成するプラスチック樹脂製の透明バック２内に、太陽光エネルギーの吸収率が高く、下面に保温層３０を配置する集蓄熱バック３を収納し、集蓄熱バック３内の蓄熱媒体Ｗに熱伝導する太陽集蓄熱バック体１を作土層５０上に延伸配置して、作土層５０を穏やかに加温蓄熱する浅層地中加温システム。【選択図】図１
