Problems That Can Arise From Relying On Wood As A Mulching Material

Wood chips are a commonly used mulching material, but many expert gardeners advise against using them because of a few significant garden problems they can create. Mulch made from wood has tendencies to cause the following six problems, making it wise to opt instead for another organic mulch material like compost, grass clippings, or straw. 

Creating a surface barrier

Over time, wood pieces have a tendency to shrink and come together to form a dense outer surface over a garden. This can create a moisture barrier that prevents water from seeping down to plant roots.

At the same time, this layer can prevent air from reaching down and circulating in the soil. This situation can incite excessive fungal growth in the soil. 

Attracting pests

Wood pieces can sometimes attract pests to a garden. Areas prone to termite infestations are especially susceptible to pest problems caused by spreading wood chips in garden areas. In addition to termites, wood can also attract carpenter ants and mice. It's especially important to avoid putting wood chip mulch up against the siding of a home to prevent pest infestation in the home's interior. 

Disrupting soil chemistry

Garden acidity is an important factor in plant health. Wood chips can throw off the pH of a garden's soil and make the environment overly acidic. 

Wood chips can also throw off garden chemistry by removing nitrogen from the soil. Wood chips cannot break down without pulling nitrogen out of the soil, and nitrogen is a substance that's important in healthy plant growth. 

Causing a fire hazard

Wood chips are highly flammable. In dry, arid climates where the temperature gets very high in the summer time, wood chip mulch can create a fire hazard. 

Necessitating excessively frequent mulch applications

Wood pieces tend to decay rapidly after they are spread over a garden. This rapid decay means that mulch will need to be reapplied frequently. Not only do wood chips decay rapidly, but they also are lightweight and can easily be blown away. 

Exposing plants to toxins

Some trees are made up of substances that could be toxic to other types of plant life. For example, black walnut trees contain toxins that can kill a wide variety of plants, including tomato, blueberry, potato, and pepper plants.

Other types of trees that are made up of potentially toxic wood include hickory, pine, and oak trees. The potential toxicity of these wood types makes mulching with wood chips risky in a vegetable or fruit garden.