A planting unit includes a plate, a hollow pillar, a first wall, a second wall, a first depression portion, and a second depression portion. The plate has a first side, a second side, a third side, a fourth side, and a first surface. The first wall is connected to the first side and the second side, and protrudes from the first surface. The second wall is connected to the first side and the second side, and protrudes from the first surface. The first depression portion and the second depression portion are respectively formed on the first wall and the second wall. The distance between the center of the hollow pillar and the third side is the same as the distance between the center of the first depression portion and the fourth side, and the same as the distance between the center of the second depression portion and the fourth side.一種種植單元，包括板體、中空柱體、第一側壁、第二側壁、第一凹陷部、以及第二凹陷部。板體具有第一側、第二側、第三側、第四側、以及第一表面。中空柱體之一端連接板體，另一端則凸出於第一表面。第一側壁和第二側壁分別連接第一側和第二側，且兩者皆凸出於第一表面。第一凹陷部和第二凹陷部分別形成於第一側壁和第二側壁上。中空柱體之中心與第三側之間的距離相等於第一凹陷部之中心與第四側之間的距離、以及第二凹陷部之中心與第四側之間的距離。
