Soil Amendments and Practices of Unproven Value

What is a Soil Amendment?

A soil amendment or conditioner is something that is added to or mixed with existing soil in order to improve soil tilth. Amendments can increase soil moisture, nutrient holding capacity, aeration, and water infiltration, among others. They can be either organic or inorganic materials. Organic matter is the most important amendment that can be added to soil and is extremely beneficial for soil health.

Unproven Soil Amendments and Practices

Unfortunately, some soil amendments, …

Materials to Improve Drainage in Soil

Materials to improve drainage in soil include organic or inorganic amendments. Organic amendments have the added capability of providing additional organic matter and nutrients.

Amendments can include bark and wood chips, compost,and pea gravel, depending on soil type. Note that mixing wood products into soil can tie up nitrogen availability. Additional nitrogen fertilizer may be necessary.

As a result of their high water retention capacity, clay soils often drain inadequately. Materials to improve clay soils differ from those needed for …

Improving Water Retention in Soil

  A sample of vermiculite. Photo credit: Brian Pettinger Flickr CC BY-NC-SA 2.0

Improving water retention in soils begins with understanding the soil type found in the garden. Soils are generally made up of varying mixtures of three sizes of soil particles; sand, silt and clay, known as soil texture.

Generally, water retention is inversely related to permeability. Sandy soils have the lowest water retention, followed by silt, and then soils high in clay.

Various soil amendments are available that …

Water Absorbing Polymers


A colored water-absorbing polymer bead soaked in water (left) and original size bead (right). Photo credit: Roger Ahlbrand Flickr CC BY 2.0

Water-absorbing polymers are long chains of molecules designed to hold large amounts of water. Water-absorbing polymers have the ability to retain up to 40 times their weight in water. While they have shown to be effective in some situations, not all situations are appropriate for water-absorbing polymers.

Water-absorbing polymers may be useful in soils with low organic