The Science of Soil Amendment: When to Use Compost vs Soil

The Science of Soil Amendment: When to Use Compost vs Soil

The Science of Soil Amendment: When to Use Compost vs Soil

Gardeners often encounter the decision of using compost or soil for their plants, and understanding the science behind each can significantly impact the health and productivity of your garden. This blog post aims to dive deep into the "Compost vs Soil" debate, offering insights and guidance on when to use each, thereby optimizing your gardening strategies.

Understanding Compost and Soil

Before delving into when to use compost or soil, it's crucial to understand what each component brings to your garden.

What is Compost?

Compost is decomposed organic matter that serves as a nutrient-rich soil amendment. It's made from various decomposable materials like kitchen scraps, yard waste, and manure. Compost enriches the soil, providing a host of benefits including improved soil structure, increased nutrient content, and better moisture retention.

What is Soil?

Soil is a complex mix of minerals, organic material, water, air, and microorganisms. It's the foundation of any garden, providing the primary medium in which plants grow. Different types of soil - such as sandy, clay, loamy - have varying characteristics that affect water retention, aeration, and nutrient availability.

When to Use Compost

Enhancing Soil Quality

Use compost when you need to enhance the quality of your existing soil. Compost improves soil structure, making it more friable and suitable for plant roots. It's especially beneficial in amending clay or sandy soils.

Providing Nutrients

Compost is rich in essential nutrients like nitrogen, phosphorus, and potassium. It's an excellent choice when your soil needs a nutrient boost, particularly for nutrient-hungry plants.

Improving Moisture Retention

In soils that struggle to retain moisture, such as sandy soils, compost can improve water retention, thereby reducing the need for frequent watering.

Balancing pH Levels

Compost can help in moderating soil pH levels, making it a good choice for adjusting the pH balance of your garden soil.

When to Use Soil

Establishing a New Garden

When starting a new garden bed or potting new plants, use soil as the primary medium. It provides the basic structure and support that plants need to grow.

Filling Large Areas

For filling large areas or creating raised beds, soil is the more practical and economical choice. It serves as the primary growth medium, while compost acts as an enhancer.

Specific Plant Requirements

Some plants prefer specific soil types. For instance, cacti and succulents thrive in sandy soil, while others may require loamy soil. Understanding the needs of your plants is crucial in choosing the right soil type.

Combining Compost and Soil

For the best results, integrating compost and soil is often the most effective strategy. Adding compost to soil not only improves soil quality but also enhances plant growth and productivity. This combination offers a balanced growing medium, suitable for a wide range of plants.


Knowing when to use compost vs soil is a key skill in gardening. While compost is best used for improving soil quality and providing nutrients, soil is essential as the primary growing medium. By understanding the unique benefits of each and using them strategically, gardeners can ensure a thriving and productive garden.


Natural + Organic Composts

Our selection of composts are made from all natural and organic ingredients designed to amend your soils to create ideal growing conditions.  

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