Wood Chips Are the Secret to Healthy Soil and Plants—Here's How to Use Them

Wood chips are an easy and affordable way to give your garden a boost. They're commonly used as mulch to suppress weeds, improve water retention, and reduce soil erosion. Beyond mulch, wood chips can be used in compost to improve its carbon content. You can also use wood chips to make pathways between rows of plants to reduce soil compaction. No matter how you use them, wood chips are an accessible material that can really benefit your yard. Ahead, experts weigh in on how to use wood chips in the garden.

Benefits of Using Wood Chips

Wood chips are an inexpensive and easily sourced material that can benefit your garden in a variety of ways.

Suppress Weeds

Wood chips act as a weed suppressor in two ways. Wood chips block sunlight, which weeds need in order to germinate and break through the soil, and they also act as a physical barrier. "The physical presence of wood chips can make it difficult for weed seedlings to emerge from the soil," says David Mizejewski, naturalist with the National Wildlife Federation. "Some weeds, such as chickweed, take advantage of bare soil to quickly germinate and colonize an area."

Improve Water Retention

Placing wood chips over the top of the soil creates a natural barrier that helps retain water, says Damon Abdi of the Hammond Research Station at Louisiana State University's AgCenter. Keeping the soil covered reduces how quickly the water evaporates. Plus, as the wood chips decompose, they improve the soil's structure, allowing it to hold more water, says Mizejewski.

Reduce Soil Erosion

When water or rain directly hits bare soil, it can cause soil erosion, especially during heavy rains, which can dislodge soil particles and wash them downstream. "A layer of wood chips limits the direct access the water has to bare soil, slows down the movement of water, and can shield soil from being washed away," says Mizejewski.

Regulate Soil Temperature

Bare soil can heat up and cool down quickly throughout the day. "A layer of wood chips can be effective at moderating soil temperatures by blocking the bare soil from the sun’s heat and serving as a cover that can insulate soil from cooling down too fast," says Abdi.

Improve Biodiversity

When wood chips break down, they add nutrients to the soil. "These nutrients help to support a wide variety of organisms, from the bacteria and fungi that help it decompose to invertebrates like insects and worms," says Mizejewski. "These nutrients also create more fertile soil that can support a wider variety of plant species."

How to Use Wood Chips

There are a few ways you can use wood chips in the garden, including as mulch, in compost, and to make pathways.

Mulch

Abdi says using wood chips as mulch can help maintain moisture, moderate soil temperatures, and suppress weeds in the garden. To insulate the roots of your plants, add a 2—to 3-inch layer over the soil.

Compost

Wood chips are carbon-rich, making them a great material to use in compost. "The ratio of carbon to nitrogen drives the decomposition process, so balancing the presence of these two nutrients is key to composting," says Abdi.

Pathways

Create pathways in your garden to limit soil compaction issues in busy areas. "Wood chip pathways in the garden can create a low impact, easy-to-walk-on surface when moving between planting rows or raised beds," says Abdi.

Types of Wood Chips to Use in the Garden

When using wood chips in the garden, choose an organic variety that's free of dyes, chemicals, and paint, says Mizejewski. Bark, cedar, and pine straw are all popular types of wood mulch to use in the garden. "As the materials break down, they contribute organic matter to the soil," says Abdi.

Considerations When Using Wood Chips

While wood chips are very beneficial when used as mulch or in compost, there are some important considerations to keep in mind.

Fungal Growth

Fungal growth is a natural part of wood chip decomposition, but some fungi may not be desirable in the garden, says Abdi. To avoid fungal growth, allow the wood chips to dry out periodically and avoid placing them in areas with low light and poor airflow.

Pests and Diseases

Always inspect wood chips for pests before using them in the garden, especially if you are unsure of where the wood chips came from. "Pest issues may vary depending on wood chip source and tree species," says Abdi. "Avoid consistently wet conditions as that can create pest issues, particularly if termites are a nearby nuisance." Additionally, you should avoid using wood chips from diseased trees as the disease can spread to the plants growing in your garden, says Mizejewski.

Limited Nitrogen

Place wood chips on top of the soil surface instead of mixing it into the soil. Wood chips, which are high in carbon, can immobilize nitrogen when they're mixed into the soil, says Abdi. Plants need access to nitrogen in order to thrive.