In an effort to save money in soil cost and improve the long term health of the soil in the raised beds, students proposed and carried out the strategy of hugelkultur in the raised beds.  A layer of large decomposing logs and sticks forms the base of the 2.5' tall raised beds.  Progressively smaller sticks and ultimately mulch and leaves are layered in until finally being finished with soil.  The organic material helps to hold moisture, promotes soil health through encouraging fungal, microbial, and invertebrate life.  As it breaks down, it's like having a built in compost in the bed.