To provide a liquid fertilizer draining device that automatically drains liquid fertilizer in a hydroponics tray with a low-cost and simple constitution.SOLUTION: A liquid fertilizer draining device according to this embodiment is capable of being fitted into a liquid discharge port provided for a tray for hydroponics for pooling liquid fertilizer used for raising plants. The liquid fertilizer draining device comprises: a drain part which, in the state of being fitted into the liquid discharge port of the tray, allows liquid fertilizer to flow under the tray when liquid fertilizer in the tray exceeds the height of an upper end； and a siphon part which has an inflow part which takes liquid fertilizer inside and an outflow part which is at a position lower than the inflow part and allows liquid fertilizer from the inflow part to flow under the tray, and is at a position substantially the same as the upper end of the drain part or at a position lower than the upper end.SELECTED DRAWING: Figure 3【課題】低コストかつシンプルな構成で水耕トレーの液肥を自動で抜く液肥抜き装置を提供する。【解決手段】本実施形態による液肥抜き装置は、植物の育成に用いられる液肥を貯留するための水耕栽培用トレーに設けられた排液口に嵌め込み可能な液肥抜き装置である。液肥抜き装置は、トレーの排液口に嵌め込んだ状態において、トレー内の液肥が上端の高さを越えたときに液肥をトレーの下へ流すドレン部と、液肥を取り込む流入部と流入部よりも低い位置にあり該流入部からの液肥をトレーの下へ流す流出部を有し、ドレン部の上端とほぼ同じかそれよりも低い位置にあるサイフォン部とを備えている。【選択図】図３
