Compost is a powerful fertilizer and makes a beautiful topsoil. Rotting and decomposing grass clippings, tomatoes and carrot-tops can be transformed into the richest soil in your backyard using easy-to-obtain materials, like an old garbage can and food scraps.
Drill 1/4 to 1/8 inch holes in the sides and bottom of a lidded plastic garbage can, using a 2- to 3-inch grid pattern.
Begin to fill the garbage can using alternating layers of "brown" material, like corrugated cardboard or newspaper, and "green" material, like moisture-rich food scraps or grass clippings.
Add a layer of organic soil to the top and spray lightly with water from the garden hose. Seal the lid of the garbage can.
Repeat the process of adding new layers every week.
Add earthworms, like red wigglers, to the backyard compost after two weeks or so. Allow the bacteria and microbes in the soil to begin the decomposition before introducing worms to the mix.
Harvest the worm castings and compost in your backyard by sifting through a wire mesh screen and distributing in the garden as topsoil.