September is a good time to begin a compost heap. Begin to layer grass clippings, dried fallen leaves, soil, a handful of fertilizer, and a little moisture. Shredded garden debris can be added as annuals and perennials die back next month.
Pick a dry day this month to test your soil. Plant Information at (847) 835-0972 has listings of soil testing agencies. Follow agency instructions on where and how to collect soil samples. Refrain from adding amendments, fertilizers, or other chemicals to your soil until you know what your soil lacks.