What Is Organic Matter and What Does It Do for My Garden Soil?

Person with gloves on holding organic matter.

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Every garden book talks about the importance of adding plenty of organic matter to your garden soil. But what is organic matter and just what does it do for soil that is so wonderful? Is it compost? Manure? Cover crops? Organic matter is all those things and what organic matter can do for your garden soil is nothing short of a miracle.

What Is Organic Matter?

Organic matter is a material that people use in gardens because of its carbon-based compounds. Gardeners use it as fertilizer to help their plants grow. Examples of organic matter include decaying plant or animal material.

A Simple Explanation

This most commonly includes compost, green manure, leaf mold, and animal manure. Moldy, decaying material may not seem like a beneficial thing to have in your garden, but the decomposition process improves the soil in several ways.

What It Does

Organic matter added to garden soil improves the structure of all types of soils, from gritty sand to heavy clay. It makes sandy soil better able to retain moisture so that it is there long enough for the plants to take advantage of. It also improves water drainage in heavy, clay soil.

Another benefit of adding organic material to the garden is that it feeds the microorganisms and insects that make up the balanced ecosystem of the soil. It creates a good environment for all these soil microbes and organisms that work with and enhance a plant's health and growth.

Also, the more beneficial microorganisms your soil can support, the fewer bad organisms will survive. That's because the good guys feed on harmful microbes, like nematodes and certain soil-born diseases. The beneficial microorganisms also release nutrients into the soil when they die and decompose. So the more beneficial microorganisms that are in the soil, the more nutrients will be in the soil.

Fun Fact

A teaspoon of good quality soil contains more living organisms than there are people on Earth.

Organic material contains acids that can make plant roots more permeable, improving their uptake of water and nutrients, and it can dissolve minerals within the soil, leaving them available for plant roots. Many organic amendments also provide some additional nutrients to the soil, although the organic matter is not considered fertilizer.

Organic matter improves the quality of your garden soil and helps to keep your garden in balance with nature. You can add it as an amendment and work it into your soil or take the easier route and use it to mulch your garden. It will eventually work itself into the soil.

Organic matter does so many wonderful things for a garden, it’s just silly not to take advantage of it. There would be no organic gardening without organic matter.

More Tips

  • Soil may look like it's just sitting there, but many elements go into making a healthy soil. It's important to know about soil texture, nutrients, and pH.
  • Don't feel bad if your garden soil doesn't measure up. Few gardens have perfect soil without amending it. Make sure you learn what your soil needs to support your plants.
  • Whether it's mulch or compost, there are simple ways to calculate how much to add to your soil.
  • Clay soil can be particularly difficult to loosen. Learn the plants that have deep roots that help break up the soil, with no effort on your part.
  • The basic premise of organic gardening is to feed the soil and let it feed the plants. Gardening organically will help keep your soil in good condition.
  • Some plants are just plain big eaters, so there will be times when feeding your plants a bit of supplemental fertilizer makes sense. Learning how to read a fertilizer label will help you tremendously.
Article Sources
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  1. Griffin, Tim. “Cooperative Extension Publications: Bulletin #2288: Know Your Soil: Soil Organic Matter” Umaine.edu. N.p., 7 July 2010. Web.

  2. Soil Organic Matter in Cropping Systems.” University of Minnesota Extension Office. Umn.edu. N.p., n.d. Web.

  3. "Soil Health Nuggets." United States Department of Agriculture. Usda.gov. N.p., n.d. Web.