8/30/2024 - By Dr. Raymond Snyder

A successful lawn, landscape, or garden is dependent on several factors that are fundamentally important such as sunlight, shade, soil, and water. But there are also agronomic input factors like fertilizer, pest management, and irrigation use that are arguably just as vital to seeing your lawn, landscape or garden thrive. Organic matter is one potential input that is easily overlooked and can make a dramatic difference in plant performance by its effect on soil productivity. In this article, we will explore the use of organic matter and how utilizing it in tandem with your applied fertilizer (such as POLYON® controlled-release fertilizer) can dramatically improve overall growth and plant health.

Why Organic Matter Matters

Organic matter imparts many beneficial agronomic characteristics in the soil such as cation exchange capacity, water retention, and soil microbiology. A cation exchange capacity is the mechanism by which positively charged nutrients are retained in the soil, making it more effective at holding nutrients in the soil and less likely to lose them to leaching. Organic matter is an excellent retainer of water which helps promote plant available water and minimize undesirable drought stress, keeping your plants healthy and preventing disease. Finally, organic matter is a home for beneficial soil microbiology and those microorganisms facilitate desirable nutrient cycling.

Sources of Organic Matter

Organic matter sources are not necessarily all the same. Organic matter properties are determined by the sources from which they are derived, for example, peat-type organic matter such as sphagnum peat has an inherently acidic pH value. Peat is an ideal organic matter input when amending high-pH soils.

Compost is another example, often derived from various, non-specific plant residues that have been microbially and thermally aged for several months. Organic matter derived from compost has a more neutral pH value and is ideal for amending acidic and mildly alkaline soil. Regardless of the organic matter source, it is important to select one that has a carbon-to-nitrogen value of 24:1 and is free of weeds and pathogens.

Amending Soil with Organic Matter

Once an organic matter source is identified and purchased it is now time to amend the soil. Increasing soil organic matter content by 1% in the top six inches of rootzone can be achieved by adding approximately 454 lb. of organic matter and mixing it thoroughly into the top six inches. Repeat 1% additions until the soil is at least 2% organic matter and up to 10% for landscapes and gardens. The greatest benefit of adding organic matter to most root zones will occur when the top six inches are amended.

Contact Your Harrell’s Rep for More Tips

In summary, organic matter inputs can dramatically increase the productivity of a landscape and garden. Choose an organic matter source that imparts beneficial characteristics in your soil based on soil-test results. Finally, incorporate organic matter throughout the effective rootzone to maximize organic matter amended soil. To learn more about organic matter sources, how it can benefit you, and any other tips you may need, your Harrell's Representative is your best resource.