Composted manure adds organic matter and micronutrients to your garden soil along with slow-release doses of essential nitrogen, potassium and phosphate. A properly constructed three-bay manure compost bin will allow the composting materials to heat up to a level that kills weed seeds and pathogens, while allowing for easy turning to aerate the pile and finish it off into a rich, crumbly matter.
Dig four holes in a straight line with a post hole digger, making each hole 2 feet deep and 4 feet apart.
Insert one 4-by-4 landscape timber vertically in each hole, and secure it by back-filling the dug soil and tamping it down.
Dig a second line of post holes, on 4-foot centers from the first line, and insert four more landscape timbers in the same manner. Do the same for a third line of posts.
Cut each of the 48 2-by-6-by-8 boards into 4-foot lengths using an electric saw or hand saw.
Fasten 24 4-foot lengths of lumber to the outside of the three rear landscape timbers, one above the other starting close to and parallel to the ground. Attach eight boards per section with the electric drill and drill bit, using two 3-inch wood screws per each end of each board.
Fasten eight 4-foot lengths of lumber to each pair of standing timbers at the ends of the compost bin array, using two 3-inch wood screws per each end of each board. Fasten eight 4-foot lengths of lumber to each pair of standing timbers within the compost bin perimeter to create two dividing walls, resulting in three separate bins, each with open fronts.
Place a 2-inch layer of pea gravel in the bottom of each bin unit. Level the gravel with a metal bow rake.
Set a layer of brick or paving tiles on top of the gravel, fitting each brick or paving tile tightly up against the next to form a firm floor.
Load the first bin with 6-inch layers of manure alternating with 2-inch layers of carbon bulking material.
Stack the remaining 4-foot lengths of lumber between the two front rows of standing landscape timbers.