Compost is the one too-good-to-be-true additive that will greatly improve the health of your garden and landscape plants. It nourishes both plants and the critters that live in the soil. Compost makes it easier for soil to receive and retain air and water, while stabilizing soil pH at a level most plants prefer. This "gardener's gold" even helps protect plants against some pests and diseases. And the best part about composting is... it is easy and free.
These publications by Iowa State Extension will help with your composting endeavors.
Composting Yard Waste - PM683
Questions About Composting - RG206
Inexpensive bulk compost is available at municipal landfills.
Iowa City Landfill and Recycling Center
Cedar Rapids Solid Waste Agency