Compost can be used just like any nutrient-rich fertilizer and it just consists of scraps that would otherwise end up in the trash. Start a compost pile by alternating layers of carbon sources (such as cardboard, straw, leaves or roots), nitrogen sources (weeds, vegetables from the kitchen or grass) and soil. Stir the pile at least every couple of weeks and keep it moist for the best results. Putting the compost in a bin can help improve the quality of the compost and deter pests from getting into it. Once the center of the pile turns black and crumbly, it’s ready for the garden.