Compost and mulch are both essential for a healthy garden and landscape, but they differ greatly from one another. In fact, mixing them up could harm your plants and the soil in your garden.
Learn the differences between compost and mulch, when to use each, and when a combination of the two is required.
Organic material in various stages of decomposition is called compost. As long as it doesn’t contain plant diseases, insects, or chemicals that could spread through the compost, it can be anything from kitchen wastes to grass clippings, leaves, manure, weeds, and plant debris.
Compost can take anything between two weeks and two years to decompose, so many other factors affect how long it takes. It’s critical for a compost pile to have the right ratio of green to brown materials. In addition, the compost needs to have the correct quantity of moisture, aeration, turning, size, ambient temperature, and worms and other creatures that break down the compost.
Uses for Compost
The most advanced type of recycling is composting. An easily absorbed form of nutrients are returned to the soil by mature compost. However, simply adding compost to a garden as a fertilizer is insufficient because the nutrient composition of compost depends on the original ingredients. especially when crops, like those grown in a vegetable garden, continually erode soils. Additionally necessary is the selective administration of nutrients in the form of fertilizer.
Compost also serves as a significant soil amendment to enhance the health of the soil. Heavy clay soils’ hard texture is loosened by organic matter, such as mature compost, making it simpler for plants to grow there. Organic stuff holds water and nutrients better than inorganic matter, therefore sandy soils at the other end of the spectrum do as well because they do not wash away as rapidly.
What Is Mulch?
Any material used to cover the soil’s surface might be considered mulch. While organic material is a necessary component of all compost, not all mulch is organic. Wood chips or shavings, hardwood bark, and softwood bark are the most widely used types of mulch, and they are offered in garden centers in bulk or bags. Pine needles, pine cones, hay, straw, cocoa, rice, buckwheat hulls, other crop byproducts, tree leaves, and grass clippings are examples of additional mulches.
Rubber, plastic sheeting, or geotextiles like cardboard, newspaper, and landscape fabric are examples of synthetic, man-made mulches. Only the final two disintegrate, whereas plastic fragments over time into smaller particles and eventually contaminate the environment as micro plastics.
Crushed seashells, gravel, pebbles, stone chips, and slate make up the third category of mulches; they are all natural materials, but they are also non-biodegradable.
Uses for Mulch
Three goals are achieved by using mulch to cover the soil in garden beds and landscapes: moisture retention, weed control, and aesthetic improvement. Mulch helps the soil retain moisture so that it doesn’t dry up as quickly. The type of mulch matters for how well it suppresses weeds; the harder it is for weeds to grow, the thicker and denser the mulch. Lastly, although it depends on personal preference, a mulched flower garden appears more orderly and tidy than one with bare dirt.
Check out if Compost and Mulch can Interchanged
It is typically not a good idea to use compost and mulch interchangeably since their purposes—soil fertilization and amendment vs. soil covering—are distinct.
However, there is a catch. When organic mulches decompose, they eventually nourish the soil with organic matter and nutrients. Decomposition of bark mulch and other woody materials takes a very long time. On the other hand, grass clippings and other fresh plant debris decay more quickly, but the soil’s microbes require nitrogen to complete the breakdown process. They seize it from any adjacent plants during that period. Chlorosis could result from this stressing out the plants. Additionally, for this reason, it is not advised to add compost to the soil until it has completely decomposed.
Point: While grass clippings should not be left in piles to decay on garden soil, they are acceptable and even encouraged to be returned to the lawn for decomposition. The grass clippings are spread out across a vast area when you mow the lawn, which is not quite as dense as when you pile them.
It can also be difficult to use mulch made of other organic components that aren’t completely degraded. For instance, failing to slice large leaves into smaller pieces before heaping them up may hinder air and water from reaching the soil. The excess moisture can result in fungi and cause root rot in nearby plants.
Best time to Use Compost vs. Mulch
Depending on your objectives, you can choose between mulch and compost. Work mature compost into the top few inches of the soil in your garden if your main goal is to enrich the soil by adding nutrients and improving its texture. Apply mulch, preferably one that decomposes over time so you receive the extra advantage of enriching your soil, if keeping the weeds down and reducing irrigation are your major concerns.
The ideal situation is to mulch your garden beds and recycle as much of your kitchen and yard waste as possible.
- Utilization of Compost and Other Landscape Refuse. Texas A&M AgriLife Extension Service.