Minecraft wiki entry for Pumpkin_and_melon_farming, associated text: The schematic shows half of tileable part of 4-growing-space floor plan. The other half is a north-to-south mirrored copy of the first half, sharing the central slice of hoppers and chests to keep iron cost low (7 hoppers per 4 growing spaces). Each growing space has 2 stems beside it. There are 2 rows of farmland between growing spaces, so each stem in the middle has 5 wet farmlands nearby, resulting in better growth rate than if the stem has less than 4 wet farmlands around. The leftmost and rightmost side of the farm should also have 2 rows of 3 farmlands to have the same stem growth rate. Not all of melon slices are collected by the hoppers, but the amount collected is probably good enough.