Compost is a dark, earthy, humus-rich material created from the decomposition of organic matter. It is highly valuable for soil health, acting as a natural amendment rather than a synthetic fertilizer. Applying compost improves the physical structure of the soil, increases its capacity to retain water, and provides a slow, steady supply of nutrients for plant growth. Integrating this material enhances beneficial microbes and fosters robust plant development.
Determining When and How Much to Apply
The timing of compost application often depends on the type of planting area, typically occurring either in early spring or late fall. For annual garden beds, spreading compost in the spring allows the soil to be amended just before planting begins. Conversely, applying it in the late fall after the harvest allows the material to settle and integrate over the winter months, especially beneficial for perennial plantings.
Determining the necessary quantity requires calculating the volume needed to cover the intended area at a specific depth. For established gardens, a 1 to 2-inch layer is recommended, which translates to roughly one cubic yard of compost for every 300 square feet. Before spreading, the compost should be screened through a half-inch mesh to ensure uniform particle size. This process removes large, uncomposted debris and guarantees an even application.
Techniques for Garden Beds and Containers
Applying compost to garden beds involves either top-dressing the surface or incorporating the material directly into the soil. In annual vegetable gardens, a 1 to 2-inch layer of compost can be spread across the entire bed using a shovel and a wheelbarrow for transport. A garden rake is then used to lightly incorporate the material, mixing it no deeper than the top 4 inches of soil. This shallow mixing helps introduce organic matter without disturbing the deeper soil structure or beneficial microbial networks.
For perennial beds and containers, compost is often used as a top-dressing, similar to a mulch. A layer of about 1/2 to 1 inch can be spread around the base of established plants, where it will slowly break down and release nutrients into the root zone over time. This surface application helps suppress weeds and regulate soil temperature and moisture levels. Established plants in the midst of their growing season may also benefit from side dressing, which involves placing small mounds of compost around the drip line of the plant for a supplemental nutrient release.
Techniques for Turf and Lawn Application
Top-dressing an established lawn requires a different approach, focusing on maintaining a very thin layer to avoid smothering the existing turf. The application depth should not exceed 1/4 to 1/2 inch to ensure that grass blades still receive adequate sunlight and air exchange. The primary purpose of this thin layer is to improve the soil composition beneath the turf, rather than feeding the grass directly. Compost encourages microbial activity, which helps break down thatch and improves the overall drainage and water holding capacity of the soil over subsequent seasons.
To achieve this necessary uniformity, specialized tools are often employed, such as drop spreaders or rotary broadcast spreaders. Rotary spreaders are efficient for large areas, distributing the fine material widely, while drop spreaders offer more precision in smaller or oddly shaped lawn sections. Dedicated tow-behind compost spreaders, which often utilize a rotating drum, are also effective at delivering a consistent, fine layer across extensive turf areas.
Once the compost has been spread, the next step is to work the material down into the canopy of the grass. This is accomplished by using the back side of a garden rake or a stiff-bristled push broom to sweep and brush the particles until they are no longer resting on the grass blades. Immediate watering after spreading is important to help settle the fine compost particles and wash any remaining material off the leaf surface, ensuring the lawn can continue to photosynthesize effectively.