Garwin soils are associated with the Muscatine and Tama soils. Garwin soils are in a hydrosequence with the somewhat poorly drained Muscatine soils and the well drained Tama soils. These soils are often surrounded by Muscatine soils. Tama soils commonly are downslope but are also upslope from Garwin soils. They also form a biosequence with the Walford soils and Traer soils.
Permeability is moderate.
Surface runoff is slow. Commonly cropped to corn and soybeans and less commonly to small grain and meadow. Native vegetation was tall prairie grasses and sedges. Minor areas in Minnesota and Wisconsin. Tama County, Iowa, 1944.