Manure is a rich organic material that improves the health and appearance of a lawn by acting as a gentle, long-term soil amendment. When applied correctly as a top dressing, it introduces valuable organic matter and nutrients directly into the root zone. This enhances the soil’s ability to retain moisture and promotes robust, deep-rooted grass growth.
Selecting the Proper Material
The most important step in using manure on a lawn is ensuring the material is fully composted or aged, which renders it safe and effective. Fresh manure contains high levels of soluble nitrogen, often as ammonia, which can severely burn and damage grass blades. Unprocessed material also frequently harbors viable weed seeds and potentially harmful pathogens that are killed during the high-heat composting process.
Composted manure is dark, crumbly, and has an earthy smell, indicating that the rapid decomposition phase is complete. Different animal sources offer varying nutrient profiles. For instance, composted chicken manure is higher in nitrogen and phosphorus, making it a potent fertilizer source. Cow and horse manure are generally milder and contribute more to improving soil structure due to their higher organic matter content. Using fully composted manure adds organic carbon to the soil, which enhances the capacity of both sandy and clay soils to manage water and aeration.
Preparation and Optimal Timing
The best time to apply composted manure is during the grass’s active growth periods, typically in early spring or early fall. Applying the material during these cooler seasons allows nutrients and organic matter to integrate into the soil without the stress of high summer heat. This timing provides the grass with a boost of slow-release nutrition before a major growth spurt or before entering winter dormancy.
Preparation is necessary to ensure an even application and prevent smothering the grass. If the compost contains large clumps or pieces of bedding, screen it through a coarse mesh to achieve a fine, uniform texture. The material must also be relatively dry, as moist compost is heavy and tends to clump, making it nearly impossible to spread evenly. A dry, fine compost will filter down easily between the grass blades to reach the soil.
Step-by-Step Application Techniques
The method for distributing the material on your lawn is known as top dressing, which involves applying a very thin, uniform layer over the existing turf. Begin by gathering the necessary tools, which can range from a simple wheelbarrow, shovel, and rake to a mechanical top dressing spreader. For large areas, a broadcast spreader designed for compost ensures the most consistent and efficient application.
If applying manually, use a shovel to place small, evenly spaced piles of the compost across the area you plan to cover. Distribute the material so the layer is no thicker than one-quarter to one-half inch. Using a leaf rake or the back of a sturdy garden rake, begin working the piles outward, dragging the compost across the lawn surface.
The final step involves ensuring the compost settles into the turf canopy and reaches the soil surface. After raking, use a stiff push broom or a drag mat to lightly brush the material, encouraging it to filter past the grass blades. A successful top dressing application results in a lawn where the grass blades are still clearly visible and the compost is barely noticeable at the base of the turf. This light dusting ensures the grass receives the benefits of the organic matter without being smothered.
Post-Application Care and Safety
Immediate post-application care focuses on encouraging the compost to settle into the soil. As soon as the material is spread, the lawn must be thoroughly watered to wash the fine particles down through the turf and into the root zone. Watering helps dissolve the soluble nutrients, making them accessible to the grass roots, and prevents the compost from forming a dry crust on the surface.
A primary safety concern is the risk of over-application, which occurs if the layer is applied too thickly. A dense layer of compost can physically smother the grass, blocking sunlight and impeding gas exchange, potentially leading to turf death. Although composted manure has a lower nitrogen concentration than fresh manure, applying an excessively thick layer can still cause nitrogen burn, especially in hot weather. Wait at least one week, and preferably two, before mowing the lawn to allow the grass blades to recover and the compost to settle completely.