What Is Well-Drained Soil?

Soil Types

• Basic soil types are sandy, clay, loam and silt. Sandy soil is grainy and crumbles easily. It does not hold shape easily and drains water freely. Clay soil is hard when dry but develops a sticky consistency when wet. It is hard to work and drains poorly. Loamy soil is considered ideal. It contains 40 percent sand, 40 percent silt and 20 percent clay. It is easy to work, holds moisture well and yet drains easily. Peat soil contains large amount of organic matter that holds moisture well and is easy to work. Silty soil contains minerals and organic matter, giving it a silky texture that makes it easy to work and moisture-absorbent.

Particle Size and Drainage

• The size of the particles contained in these various soil types determines the quality of drainage, as well as its ability to hold nutrients, according to the University of Illinois Extension Service. Sand has the largest particles. This causes it to drain very easily, so it cannot hold nutrients well. Clay soil has the smallest particles. It can hold nutrients but does not allow water or air to flow through it easily. Silt soil particles are in between sand and clay sizes. It can hold nutrients, yet allows water to flow through it well. If your garden soil does not have enough large particles in it, it will not allow enough drainage for plant roots. The roots may sit in watery soil for long periods of time. This causes root rot and may cause other soil-borne diseases.

Testing Your Soil

• Some quick and easy ways are available to help you determine what type of soil you have. For the squeeze test, take a handful of soil and squeeze it hard. Clay will ooze between your fingers and hold its shape when you release your hand. Sandy soil falls apart easily when you release and feels gritty to the touch. Loam soil will hold its shape when you release it but breaks apart easily when you poke it, according to the National Gardening Association site. Silt and peat soils will also break apart when touched.

Improving Soil Drainage

• You can improve the quality and the drainage in your soil by adding soil amendments, such as compost, sphagnum peat moss, processed manure, dried leaves, straw, sand and other materials to increase the amount of "spaces" between the soil particles. These should be worked thoroughly into the soil to be effective, not just laid on the surface of the soil or buried beneath the topsoil, according to Colorado State University soil specialists, J. G. Davis & C.R. Wilson.