All soils are composed of sand, clay, silt and organic matter. The difference in soils is due to the different compositions of those ingredients. Some soils have more sand while others have more clay. The relative amounts of each of a soil's ingredients determines how compact the soil is and how well (or poorly) a soil drains. Soil drainage can also be affected by how close to the surface the water table is; the closer to the surface, the more poorly your soil will drain. Many plants do not grow well in poorly drained soil.
Check the color of your soil. Well drained soils are usually brown or red. Poorly drained soils are often gray.
Dig down into your soil. You should begin digging in brown or black soil. Note the depth when you reach a gray or mottle layer of soil. This gray soil will be dense and clay-like. If this gray layer is within a depth of 18 inches, your soil may be poorly drained. Well drained soil has approximately 30 inches of depth until you reach the gray or mottled layer (known as the limiting layer) of soil.
Dig a hole approximately 12 inches deep and 12 inches in diameter. Fill the hole with 2 gallons of water. See how long it takes for the water to completely drain away into the soil. If it takes more than an hour, you have poorly drained soil.
Add sand, peat and manure to your soil to improve the drainage if your soil has poor drainage.