What is organic matter anyway?

Organic matter is the cornerstone of fertile soil and a vibrant garden, but what do we mean when we say organic matter? It refers to the various forms of living, or once-living, material that can be incorporated into the soil to improve its quality and fertility. Let's explore this natural boon and how it can be harnessed to enrich our gardens and landscapes, and look at some examples of products or components you can use in your own space.

The Essence of Organic Matter

Organic matter in the soil is composed of plant and animal residues at various stages of decomposition, cells and tissues of soil organisms, and substances synthesized by soil organisms. It's a vital component for soil health, providing nutrients, improving soil structure, increasing water retention, and fostering microbial life as we discussed in the prior blog post.

Sources of Organic Soil Amendments

There are numerous sources of organic matter that can be added to the soil as amendments, each with unique benefits:

Compost: The Gardener's Gold

Whether you make it at home, or purchase it locally compost is decayed organic material, and is one of the best ways to add life to your soil. You can create your own compost from kitchen scraps, yard waste, and other organic materials - stay tuned for more on how to compost at home! It's rich in nutrients and beneficial microorganisms that help plants thrive.

Manure: Time-Tested Fertilizer

Manure from animals such as cows, horses, and chickens is a traditional soil amendment that's high in nutrients, especially nitrogen. It's important to use well-composted manure to avoid the introduction of pathogens.

Leaf Mold: Forest's Gift

Leaf mold is decomposed leaves, which you can collect and compost from your own yard. Forgo bagging them up and letting the city take them away, simply run over them with a lawnmower, or alternatively put them in a trashcan and use a weed-eater to chop them up! It’s an excellent soil conditioner, improving structure and water retention while adding back nutrients to the soil for the next growing season.

Green's/Cover Crops: Living Amendments

Plants grown specifically to be tilled back into the soil, such as clover, vetch, and rye, are known as green manures or cover crops. They add organic matter, suppress weeds, and can prevent soil erosion. Typically cover crops are sowed in autumn and allowed to enrich the soil over the off-season. Come spring these crops can be tilled in to enrich the garden. Cover crops can also be used during the growing season if you are allowing a planting bed a rest season.

Wood Chips and Sawdust: Carbon Rich

While these are high in carbon and low in nitrogen, they can be beneficial when used as a top dressing or mulched into the soil slowly over time. They are particularly good for improving soil structure. Go light on fresh wood chips though! It is best to compost bark fines and allow them to age before incorporating them into the garden.

Peat Moss: Acidic Amendment

Peat moss is often seen in garden centers and available online from retailers at a fairly low price point. Peat moss is often used to add bulk to the soil, improve water holding capacity, and is particularly good for acid-loving plants. However, it's not a renewable resource, so many gardeners look for more sustainable alternatives.

Worm Castings: Nature's Soil Conditioner

Worm castings are the end-product of the breakdown of organic matter by earthworms, and arguably one of the best ways to enrich your garden soil both for edible crops and in the landscape! Earthworms are incredible creatures and act to aerate the soil as well as increase beneficial bacteria and fungal colonies. Providing a conducive habitat for earthworms means you are setting yourself up for success! Earthworm casting are incredibly rich in nutrients and beneficial microbes.

Incorporating Organic Matter into the Garden

Adding organic matter to your garden isn't just about dumping compost or manure onto your beds. It's about understanding the needs of your plants and the current state of your soil. So before you go off and load up on cow droppings (peee-eeewww) lets first take a look at some key principles of how to go about adding organic matter into the garden.

Testing Your Soil

If you’re nerdy like me, or simply curious about the condition of your soil before adding anything, it may be a good idea to test your soil to understand its current composition. There are a variety of online tests that you can purchase that are fairly inexpensive, as well as reaching out to your local exchange office to see if they offer the service. This will guide you on what amendments it might need and in what quantities. Sometimes knowing before-hand what is needed can save you a headache in the future!

Application Techniques

For compost, manure, and leaf mold, work them into the top few inches of your soil or spread them as a top dressing. Active soil microfauna will go to work incorporating these materials into your soil. With green manures, plant them at the end of the growing season and then till them under in the spring, or overlay fresh manures with hay or bark chips and allow to compost first. For wood chips and sawdust, use them as mulch around plants, being careful not to let them touch plant stems or trunks. Allowing wood chips to age first is preferred.

Timing Matters!

The best time to add organic matter is either in the fall, allowing it to decompose over the winter, or early spring before planting (if it is already aged). Some amendments, like worm castings, can be added at any time, as well as ready-for-use products like Espoma’s Land and Sea Compost!

Quantity and Quality

More isn't always better. Sometimes we have a propensity to chuck more and more material at our gardens. Add only what your soil needs, as indicated by your soil test, or seasoned gardener. Also, ensure the quality of your organic matter; for example, manure should be well-composted and sawdust should be free of any chemical treatments. Quality over quantity!

Benefits of Organic Matter

Now don’t get me wrong, that doesn’t mean you just need to go out and sprinkle a few coffee grounds over the soil surface and call it a day… The benefits of adding organic matter to your garden are numerous!

• Nutrient Supply: It releases nutrients slowly over time, which are then available for plant uptake.

• Water Retention: It helps soil retain moisture, reducing the need for frequent watering.

• Soil Structure: It improves soil aggregation and porosity, making it easier for roots to grow.

• Microbial Life: It supports a diverse soil microbiome, which in turn supports plant health.

A Sustainable Approach

Using organic matter as a soil amendment is not only good for your garden, it's good for the planet. It recycles waste, reduces the need for chemical fertilizers, and can help sequester carbon in the soil.

In conclusion, organic matter is the lifeblood of a healthy garden. Understanding its sources and how to properly apply it to your soil can lead to a lush, productive, and environmentally friendly landscape. As gardeners, our role is to act as stewards of the soil, and utilizing organic matter is a fundamental part of that stewardship.