How to Make Commercial Compost

Prepare land for windrows. Lay a strip of liner fabric in a straight line that is at most 20 feet long. Cover with a 1-inch layer of gravel. Dig a drainage system next to the graveled path that allows water to run off easily and flow into a containment system.

Grind waste materials into uniformly sized pieces. The pieces should be large enough that they won't fly off the pile when it's windy. Grinding compost materials increases the surface area available to bacteria and speeds decomposition.

Mix nitrogen-rich and carbon-rich materials together, using a manure spreader or front-end loader. The ratio of carbon-rich material to nitrogen-rich material should be 30 to1; 50 to 1 is the highest carbon to nitrogen ratio that facilitates proper composting. Moisture level in the mixture should be between 40 percent and 60 percent.

Apply mixture to windrow. Using the manure spreader or a dump truck, spread the mixed materials on top the graveled windrow. Continue adding layers until windrow reaches 10 feet in height or a height that turning equipment can accommodate.

Spray layer with probiotic inoculant. Inoculants add beneficial microbes to the pile that accelerate the rate at which debris break down. Mix the inoculant solution according to instructions and apply to each layer using either a compost turner with a watering attachment, or a tractor-mounted tank sprayer.

Turn compost weekly to aerate the windrows, using the compost turner. Aeration speeds decomposition and minimizes odors. During droughts, add moisture if the materials become too dry and stop decomposing. Repeat until active decomposition is complete. The windrow should be finished composting in 90 days.

Cure the compost. Move finished compost from the windrow to a covered storage facility with a cement floor in order to cure. During this time, materials will still be decomposing but at a slower rate and will not generate a lot of heat. Maintain a moisture level of 40 to 50 percent and cure for a minimum of one month. Allow to dry to 40 percent moisture or lower prior to screening.

Screen out rocks, plastic or metal contaminants and large pieces of material that may not have decomposed thoroughly, using the screens. The fine particles of compost are ready to package, sell as bulk material or spread on cropland.