What Is Organic Matter? Benefits for Soil & Gardening
When it comes to soil health, organic matter is not just a bonus it’s a necessity. Whether you’re growing vegetables, planting flowers, or designing a new landscape, understanding the role of organic matter can transform your garden’s performance from average to amazing.
What is Organic Matter?
Organic matter is any plant or animal material that returns to the soil and goes through the process of decomposition. This includes:
- Compost
- Fallen leaves
- Grass clippings
- Manure
- Dead roots and organisms
As it breaks down, it enriches the soil with essential nutrients, improves soil structure, and increases water retention.
Why Organic Matter is Essential for Soil Health
Adding organic matter to soil offers numerous benefits:
- Improves Soil Structure: Makes clay soils looser and sandy soils more cohesive
- Increases Water Holding Capacity: Vital for drought-prone areas or summer gardening
- Boosts Microbial Activity: Healthy soil biology = healthy plants
- Enhances Nutrient Availability: Releases nitrogen, phosphorus, and potassium naturally
- Supports Root Development: Encourages stronger, deeper roots in flowers and vegetables
Where to Use Organic Matter
You can add organic matter to:
- Vegetable gardens
- Raised beds
- Lawns
- Shrubs and tree bases
- Rain gardens and wildflower turf
How Much Organic Matter Should You Add?
The ideal amount depends on your project size and existing soil conditions. A general rule is to add 2–3 inches of compost or organic matter and mix it into the top 6–8 inches of soil.
If you’re unsure how much you need, try using our Topsoil Calculator to estimate the volume of soil and compost required based on your area’s dimensions.
Tip: Compost is the Best Organic Matter
Well-aged compost is rich in microorganisms, easy to work with, and highly effective as a soil improver. You can create it at home or purchase it in bulk.
Rebuilding Soil with Organic Matter After Construction
In areas impacted by heavy machinery or grading, like post-construction sites, adding organic matter is essential. It helps restore the soil structure and support long-term plant health.
Many municipalities (like King County) even require a specific amendment rate to meet soil standards for new developments.
Environmental Benefits of Organic Matter
- Reduces soil erosion
- Improves carbon sequestration
- Supports biodiversity
- Promotes sustainable gardening
Final Thoughts
Whether you’re rejuvenating tired garden beds or starting fresh with a new landscape design, organic matter is your soil’s best friend. It’s natural, effective, and essential for long-term success.
Don’t forget to check how much soil and compost you need with our free Topsoil Calculator it takes the guesswork out of gardening and ensures your plants have the perfect foundation.
