When they are full, their contents are dampened, mixed with some soil, and covered with sailcloth. After five to eight months, the product can be used as fertilizer. A mulberry tree planted in this fertilizer grew so well that it was the envy of a nearby silkworm farmer. He'd come onto the school grounds late at night and pick off all its leaves, prompting the school to step up patrols.
箱子堆滿後，經過簡單的灑水、加入泥土攪拌後用帆布封蓋，5 至 8 個月之後即可取出當作肥料；種出的桑樹還因長得太好招致附近蠶商的嫉妒，竟半夜潛入校內拔光桑葉，逼使校方只好加強巡邏。