Whether you’re growing flowers, vegetables, shrubs, or herbs, healthy and high-quality soil is a must-have for a thriving garden. Both plants and plant-friendly microorganisms flourish in soil that’s rich in nutrients, has good water drainage, and is resistant to weeds and pests.
Most gardeners are aware of the need to regularly apply fertilizer for optimal plant growth, but did you know that compost and mulch are important for your soil quality as well?
Although the terms are sometimes used interchangeably, compost and mulch have different purposes and offer unique soil benefits. In this guide, I’ll share the key differences between them, as well as the surprising benefits of using compost or “black gold” for mulching.
Mulch vs. Compost: What’s the Difference?
Mulch is a material that you use to cover the surface of your soil to retain moisture, suppress weeds, and enhance the visual appearance. It also prevents topsoil runoff during rainy days and regulates temperature, keeping your soil cooler in the summer and warmer in the winter.
The most common forms of mulch that you can use are wood chips, softwood bark, pine needles, hay, and grass clippings. Synthetic mulches made of rubber, plastic, and geotextiles are also available.
Meanwhile, compost refers to organic material that undergoes various stages of decomposition. Fully decomposed compost turns into organic matter that’s dark brown in color and incredibly rich in nutrients, which is why some gardeners call it “black gold.”
Unlike mulch that lays on the soil surface, compost is used as a soil amendment that’s tilled and incorporated into the ground to nourish plants and enrich the soil. Compost can include manure, leaves, and even scraps from your kitchen, such as carrot peels, old bread, and coffee grounds.
Can You Mulch With Compost?
Yes, it’s possible and highly beneficial to mulch your garden using compost. It’s also cost-effective because making compost out of yard waste and food scraps allows you to get shovelfuls of free mulch—you won’t need to buy bags of wood chips from the store anymore.
Compost is a great organic fertilizer, and covering your topsoil with it supports earthworms and microbial activity within the soil. When it rains, water runs through the compost and pushes nutrients further into the soil while retaining enough water to sustain your plants.
A layer of compost also prevents weeds, but note that your compost should be properly prepared to prevent weed seeds from surviving and infiltrating your garden. Well-made compost produces natural heat that kills harmful bacteria and most weed seeds.
Although compost is fine to use as mulching material for your garden, the reverse isn’t recommended—you can’t use mulches for composting, especially if you plan to till your soil. Mulches, such as wood chips, rocks, and stones, aren’t suitable and effective for composting.
Benefits of Mulching With Compost
Many organic gardeners consider compost as the “best mulch” due to its versatility and the countless benefits it offers, including:
- Adds life-sustaining nutrients to the soil
- Speeds up the growth of plants
- Reduces damage from pests and diseases
- Promotes soil-friendly microbial activity in the soil
- Produces bigger vegetables and flowers
- Holds on to more water than other mulch materials
- Blocks the growth of weeds
- Aerates the soil and prevents soil erosion
- Helps regulate soil temperature
- It’s more accessible and affordable than other types of mulch
It’s important to note that the quality of the compost, including the nutrient content of the materials used, has a great impact on how the compost performs when added to the soil.
How to Use Compost for Mulching in Gardens
Before you apply compost as a mulch in your annual or perennial garden, clear away any weeds, stray rocks, and unwanted grass on the ground. Then, distribute two to three inches of compost directly on top of the soil and even out the compost layer with a rake.
Leave some space between the mulch and the base of your trees and plants, as piling up organic matter against them can cause root rot and fungal infection. You might need to add more compost regularly throughout the growing season to continue enjoying its benefits.
It’s worth mentioning that the best compost for mulching is finished, screened, and homemade compost. Finished compost won’t rob nitrogen from the soil, and screened compost is even and free from irregular bits of matter that take longer to break down.
If you decide to purchase compost instead of making your own, choose compost that’s produced using the hot composting method to ensure that weed seeds and harmful bacteria have been neutralized.
Final Thoughts
Cultivating fertile and high-quality soil is the ultimate goal of every gardener. One way to keep your soil healthy and your plants happy is to mulch regularly, using nutrient-rich compost.
Compost is a simple, affordable, and eco-friendly alternative to store-bought forms of mulches, and its benefits range from pest prevention to water retention and temperature regulation.
Don’t miss out on the advantages of this versatile material, and start mulching your garden using compost today!
Ben has a bachelor’s degree in construction engineering. When not constructing or remodeling X-Ray Rooms, Cardiovascular Labs, and Pharmacies, you can find him at home with wife and two daughters. Outside of family, He loves grilling and barbequing on his Big Green Egg and Blackstone Griddle, as well as working on projects around the house.
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