The benefits of wood-chip paths

Principles in Action - Pathways

As featured in the Hunter Organic Growers Society Newsletter - January 2023
Each month, I will be sharing an example of permaculture principles in action on our farm. The principles are integrated concepts, as such, I hope to illustrate how we apply several in concert when decision making.

Back in winter, I relaid the wood-chip pathways between the step-over beds in our market garden.

We prefer wood-chips to gravel, weed mat, or living pathways in this situation for the numerous benefits they hold as a pathway material. They keep our feet dry, suppress weed growth when laid deeply, retain moisture, and provide the medium for a terrific fungal network to exist across our garden. They are a biological solution and represent the use of a renewable resource, that in a closed-loop system can be readily produced to the quantity needed on a small acreage like ours. While we are always trying to reduce inputs, when we do have to introduce an external influence to the property we look to use an organic or biological agent, rather than the alternative such as weed matting, due to the embodied energy. The aim to produce no waste is all the more possible when using biological resources over artificial ones, because everything gardens and will cycle natural elements through the food web.

Over time, the wood-chips are decomposed by the microorganisms living between our beds. We value this edge environment, looking at the pathways, just wide enough for a wheelbarrow, as a powerhouse of soil building. Nutrient cycling is happening here, and we are catching and storing this energy. The breakdown of the wood chips means we do have to replenish the paths about every twelve to eighteen months, depending on the weather conditions. The problem is the solution here, however, as we creatively respond to the change in the decomposed wood-chip, as it has now become excellent compost material, which we used to fill the raised beds in the foreground of the accompanying photograph.

Among many gardening myths, there is the notion of wood-chips ’nitrogen-robbing’ the soil. The wood-chips do no such thing, but the soil micro-organisms do require nitrogen as they get on with decomposing the freshly added source of carbon, among other elements, to the garden. Indeed, a genuine movement of nitrogen does take place, but we must remind ourselves to observe and interact with our garden in a cycle, not just the point in time that we perceive the problem. The nitrogen will be returned in the long term.

The decomposition of the wood-chips occurs over several cycles, as different microbes and fungi specialise in breaking down the cellulose, lignin and other wood-chip constituents over different intervals. They are a (very, very) small and slow solution that we use to complement our own compost building, to ensure we are always building soil, a critical regenerative practice.

The soil populations require nitrogen, phosphorous, and other nutrients from the soil for growth, so the concern is that this is ‘robbed’ from our soil, and thus is not available to our plants. The effect is localised however, so if the wood chips are not incorporated into the soil (which they are not as we practise no-till methods), but just on top, then it’s only a surface level problem. Consider the root zone of your crops, and also where weed seed germination is taking place. Soil organisms locking up some surface level nitrogen could actually help in weakening the growth of weeds at that level.

While we’re on the subject of nutrients, there are of course different choices of hardwood, cedar, pine bark, etc for your wood-chips. A great approach is consider the value of diversity. A mixed load that contains plenty of smaller diameter, young, and green branches (referred to as ramial wood-chips, as in ramus=branch) will introduce a higher ratio of nutrients to your garden, making for a great mulch around your perennials.

At an observed and practical level, our use of wood-chips between growing beds has been going on for a few years now, and we are yet to observe any negative impact on crops - just beautiful, rich compost after the wood-chips have performed their role in the pathways. The selection of any resource can be guided by the principles, looking for multiple functions to bring to the garden.

Maplewood Permaculture Farm,
December 2023