The Dirt About Organic Matter for Gardens

Soil may not sound sexy. But healthy soil with organic matter is critically important for growing gorgeous gardens. You don’t need much organic matter either – about 5 to 6 percent in your soil is ideal. But the benefits of these small amounts of organic matter are huge.

Learn the dirt about organic matter, and why it’s important for your garden.

Healthy soil photo via NRCS/Flickr Creative Commons

What is organic matter for gardens?

Soil organic matter is “made up of plant and animal residues in different stages of decomposition, cells of soil microorganisms, and substances that are so well-decomposed it’s impossible to tell what they were to begin with,” according to University of Vermont Extension.

It’s important to remember that healthy soil contains literally billions of living organisms, such as single-cell bacteria, protozoa, fungi, microscopic nematodes and other soil-dwelling insects like earthworms.

Over time, these soil organisms decompose different organic materials into humus, which improves the physical and chemical attributes of garden soil in several different ways.

How does organic matter benefit the garden?

• Supplies nutrients for the soil and plant growth.
• Creates better soil drainage by improving the structure and permeability.
• Reduces the risk of soil erosion.
• Stores water in the soil.
• Buffers the soil pH so it remains stable.
• Encourages growth of healthy soil microorganisms and earthworms.

Mulch photo by Flickr Creative Commons

Add organic matter regularly

Building a humus-rich soil takes time. One of the best things you can do for your soil is to add a couple inches of organic materials each year.

For example:

• Add compost and manure into the top few inches of soil.
• Mulch garden beds with organic materials, such as fine wood chips or compost.
• Chop your fall leaves finely with a lawn mower, and leave a thin layer on the grass.
• Plant cover crops during off-seasons to help increase organic matter, too.

Things to consider

Want to maintain adequate levels of organic matter in your soil? Consider these points:

• Organic matter decomposes faster in hot, humid weather than in cool or dry climates.
• Clay soil tends to have more organic matter than sandy soils.
• Tilling the soil can speed up the decomposition of organic materials. Use mulching methods, or gently work the organic materials into the soil with hand tools. Don’t over-cultivate the soil.
• Protect the topsoil in your garden — this is where most organic matter resides.
• Avoid erosion issues, which can wash away your organic matter too.

So, this year, make a commitment to build humus-rich soil in your garden. The dirt about organic matter is that your garden soil needs it very much.