Finding free homemade mulch for your garden.
A good source of free homemade mulch for large areas is tree trimming and removal companies. Usually arborists pay to dispose of tree trimmings and will gladly give the whole batch to you, if you want it all. Of course, truck size and content varies, but you might receive 10 cubic yards of wood chips free.
Coarse chipped wood makes fine mulch. A truckload of newly chopped tree material can contain enough chipped green leafy matter to get very hot, cooking your plants. Do not allow green mulch to touch plants as you cover the area. Reducing the chipped woodpile to a layer of 2 or 3 inches can lower the increased temperature.
If there is space to stockpile it, wood chips will break down in two or three years, making a good ready source of carbon-rich materials to add to the compost pile. The brown portion of compost — the twigs, branches, dried leaves, etc. — supply the bulk carbon to the compost pile, while the fresh stuff — "greens" like clippings, weeds, coffee grounds, or veggie scraps — supply a lot of the nitrogen and some moisture. Commercially chipped wood from a landscaping service can be run through a home chipper/shredder to create smaller, more attractive mulch. Supplement with additional nitrogen.