To provide a plant cultivation tool capable of suppressing efficiently, temperature rise of a root growing body in a plant cultivation tool storing in a container, the root growing body, a plant cultivation tool formation material, a separation space holding part formation material, and a temperature rise suppression method.SOLUTION: A felt-like root growing body C is stored in an inner peripheral part of a container B, and a separation space holding part R for holding a separation space part P in which, a moisture of the root growing body C may be vaporized from an outer peripheral part, is arranged between an outer peripheral part of the root growing body C stored in the container B and an inner peripheral part of the container B. The separation space holding part R is formed of a lattice-like part R1 and a plurality of rod-state support bodies R2. The lattice-like part R1 of the separation space holding part R is along the outer peripheral part of the root growing body C, and the support bodies R2 of the separation space holding part R support the lattice-like part R1 to the inner peripheral part of the container B for maintaining a prescribed separation distance between the inner peripheral part of the container B and the outer peripheral part of the root growing body C.SELECTED DRAWING: Figure 2【課題】 容器内に根生育体を収容してなる植物栽培器における根生育体の温度上昇を効果的に抑制することができる植物栽培器、植物栽培器形成材、離隔空間保持部形成材及び温度上昇抑制法の提供。 【解決手段】 容器Ｂの内周部にフェルト状の根生育体Ｃを収容し、容器Ｂ内に収容された根生育体Ｃの外周部と容器Ｂの内周部の間に、根生育体Ｃの水分が外周部より蒸発し得る離隔空間部Ｐを保持するための離隔空間保持部Ｒを配置する。離隔空間保持部Ｒは、格子状部Ｒ１と棒状の多数の支持体Ｒ２からなる。離隔空間保持部Ｒの格子状部Ｒ１が根生育体Ｃの外周部に沿い、離隔空間保持部Ｒの支持体Ｒ２が容器Ｂの内周部に対し格子状部Ｒ１を支持して容器Ｂの内周部と根生育体Ｃの外周部の間に所定の離隔距離を維持する。【選択図】 図２
