Minecraft wiki entry for Pumpkin_and_melon_farming, associated text: The floor consists of farmlands and dirt in the checkerboard pattern. There are hoppers under farmlands and they are connected to a storage container(s). One block of dirt is replaced with water in every 9х9 area. Pumpkin seeds and melon seeds are planted in alternating rows, so their diagonal stem neighbors are of a different kind from themselves. On dirt, blocks are air blocks and on these air blocks are pistons facing down. On the same level as pistons, jack-o'lanterns are placed over stems and farmlands column. The pistons and jack-o'lanterns are in a checkerboard pattern. Redstone pulses from clock are sent to one opaque block on piston, then spread through redstone repeaters and redstone dusts, which are on jack-o'lanterns, and more opaque blocks on pistons. Appropriate clock cycle period may be around 5-6 seconds or longer.