When choosing the mulch for your garden or landscape, one option is organic mulches. The mulches come from plant material that decomposes easily and has several benefits to both the oil and plant. Here are some of the impacts:

  • Physical Effects

2812559_orig (2)Organic mulches change the soil’s structure, and this increases the root growth. The addition of mulches such as leaves and shredded barks to the soil has an almost instant impact. In clay soils, organic mulches improve aeration while in sandy soils; the mulches increase the water-retention capacity. If the organic mulch has not undergone decomposition, the mulch can enhance granulation.

When you cultivate the soil when it is too wet, you destroy its good structure. However, when you use mulches, you reduce or eliminate cultivation. Organic mulch also acts a cushion and minimizes the damage that people cause as they walk through the garden when the soil is wet.

  • Chemical Effects

mulches_800The use of organic mulches also affects the soil pH. Many organic mulches increase the pH slightly and make the soil reaction more alkaline. Since organic mulches contain plant materials, they add little quantities of nutrients to the soil as they decompose. These amounts have little impact on the nutrient levels in the soil so you should not consider them a substitute for fertilizer. The micro-organisms that decompose organic matter use a significant amount of nitrogen when you use fast decaying organic mulches. As a result, the nitrogen reserves in the root zone of the plant reduce and if there are no regular additions of nitrogenous fertilizer, there can be a nitrogen deficiency.

  • Biological Effects

Organic mulches act as food for most of the microorganisms in the soil that are useful in maintaining and enhancing the soil granulation. The mulches also maintain the temperature of the soil at a constant so that the microorganisms can carry on with their activities at an even rate.


Harmful organisms such as bacteria, fungi that cause diseases and nematodes can sometimes get into the soil through organic mulches. Molds also grow on extremely wet organic mulches. You can make a habit of stirring organic mulches occasionally to enable the surface to dry fast and reduce the molds. Rodents and insects can also hole up in some organic mulches take precautions to avoid these problem-causing organisms. You can also introduce weed seeds to your garden when you use hay or straw so ensure they are free of seeds or grains before using them as mulch.

You can know more about organic mulch and the effects it has on your garden or landscape at Open Permaculture and Regenerative Leadership Institute online.