Wood chip is something that many gardeners buy for their gardens. Some also have a garden shredder and make their own. Whether you buy it or make it, it can be a very useful natural resource. But it is important to understand how and where to use it (and how not to use it) in your garden.
In this article, we’ll explore how to use wood chip in a little more depth. We’ll talk about the different types of woodchip. And we’ll explore some of the main ways to use it in your garden. Read on to find out more about the benefits of using wood chips, and some of the downsides to using it in certain ways.
Types of Wood Chip
Before you start to use wood chip in your garden in any way, it is important to consider a few things:
Wood chip is useful for different things depending on what type of tree it came from.
It comes in a huge range of different sizes, or grades, textures etc…
Some commercial wood chips have been treated, and may not be quite as eco-friendly as you imagine. Know your source, and try to choose sustainable options.
Making your own wood chip in your garden can be a sustainable choice – especially if you run a garden chipper or shredder using a renewable electricity supply.
How Can You Use Wood Chip in Your Garden?
Certain types of wood chip can be used in your garden:
As a mulch
In certain composting systems.
To make new growing areas.
As a substrate for growing mushrooms.
To make your own biochar to enrich your garden.
As a path material.
To cover the ground in a chicken run.
As livestock bedding.
For a seating area or play area.
To create wildlife habitats.
However, it is important to use the right type of wood chip for the right applications. And there are caveats involved when it comes to using woodchip in certain ways – especially when using it as a mulch or in composting systems.
Mulching With Wood Chip
Wood chip can also be extremely useful as mulch. But you do need to be careful where you use it. It is great around fruit trees, mature shrubs and woody perennials, but is not necessarily always such a good idea in a vegetable garden.
First of all, when thinking about mulching with wood chip, you need to think about how large the chips are. Larger pieces will take longer to break down, so are better as a longer-lasting mulch around trees etc… It will also make a difference whether the wood chip was dried or partially dried harvested wood that was chipped, or green wood along with some foliage from your garden.
The wood type will also be a consideration. Hardwood wood chips have different properties to softwoods like pine. If using a conifer, for example, it is important to note that it can acidify the soil. This could be beneficial for areas with alkaline soil – but may be undesirable where ericaceous soil is found. Certain woods, like walnut, contain juglone – a biochemical that retards the growth of nearby plants. So don’t use it around plants affected by this allelopathy.
Fungi and Bacteria
Using wood chip as a mulch also requires careful consideration because using it can affect the composition of soil micro-biota.
One reason that wood chip can be good to use around trees and woody shrubs is that it helps to nurture a fungal environment – like that of a natural woodland or forest, where there is typically a fungi-bacteria ratio of 10:1 – 50:1.
In an annual garden, the fungal/bacterial ratio is generally around 0:3 to 1:1. Wood chip can alter this ratio, making it more fungal. This can potentially be detrimental over time in a vegetable garden.
Issues With Nitrogen
It is usually not a good idea to place a mulch of wood chip on its own around annual vegetables for another reason too. As the material breaks down, nitrogen is sequestered by micro-organisms. Since the material itself is low in nitrogen, the micro-organisms involved in decomposition must get it from elsewhere. This can deplete nitrogen from the surrounding soil.
It is not a good idea to mulch seedlings and annual plants with just fresh wood chip in part because many require plenty of nitrogen during the time that the wood chip is breaking down.
However, you could consider adding wood chip as a mulch, even in an annual vegetable garden, if you add a nitrogen-rich mulch material at the same time. When you do this, there will still be plenty of nitrogen to go round even while the decomposition is taking place. (Green wood with some foliage passed through a garden shredder will already have this nitrogen rich material built-in.)
Composting Wood Chip
Another option to consider is composting (or partially composting) the material before you use it as a mulch. When it is composted, decomposition will already have taken place and so the nitrogen depletion described above will no longer be an issue.
Wood chip can be an excellent material to use as a carbon rich or brown material in a composting system. However, it is important to make sure that it is kept in balance with nitrogen rich or green materials for best results.
In addition to adding it to a typical heap or composting bin, you can also compost it in place in your garden. You can make new garden beds with layers of brown and green materials that will break down to make new, fertile growing areas. Lasagna gardens and hugelkultur mounds are two examples to new growing areas that you can make with a range of organic materials – including wood chip.
Allowing it to break down on pathways, seating areas or play areas before you use it in your garden beds is another way to allow it to compost before you use it in your garden.
Making your own biochar (charcoal inoculated with compost tea or other liquid feeds) is another way to add fertility to your garden. And chips of wood can be used in making your own.
Growing Mushrooms in Wood Chip
One thing that you can grow in wood chip alone is mushrooms. This material can be an excellent thing for fungi – including the fruiting bodies of fungi that we eat. It can be used as a substrate for a number of different edible mushrooms. So if you want to branch out from growing plants in your home growing, this could be something to consider.
Using Wood Chip As Ground Cover
Remember, if you plan to use your wood chip as pathways, or to protect the ground and avoid muddy spots in seating areas or play areas, the size of the chips is the most important thing. Larger chips will last much longer, and greener, sappier wood will break down more quickly.
In many cases, you will want to material to remain for as long as possible, so larger chips will be best. But where the pathways are through a growing area, and you later want to use the material as a mulch, you could consider deliberately choosing chips that will break down more quickly. You can use the decomposed material and replenish it more frequently.
There are special considerations when you want to use it as ground cover or bedding in a chicken run or livestock enclosure. Make sure you choose a type that will not hurt the animals, or cause issues with mould growth and spores.
Creating Wildlife Habitat With Wood Chip
Finally, when using this material to create habitat for wildlife, remember that it can be used in a range of ways. Even making heaps with wood and other organic material will attract many beneficial creatures and make them welcome in your garden. But you can also use the material as you make dedicated houses, boxes or ‘hotels’ for certain specific creatures.
Just make sure you do not use any treated wood that could cause harm to wildlife in your garden.
The tips above should have given you a better idea of how to use wood chip (and how not to use it) in your garden. If you have additional tips to share, please do so in the comments below.
Elizabeth Waddington is a writer and green living consultant living in Scotland. Permaculture and sustainability are at the heart of everything she does, from designing gardens and farms around the world, to inspiring and facilitating positive change for small companies and individuals.
She also works on her own property, where she grows fruit and vegetables, keeps chickens and is working on the eco-renovation of an old stone barn.
To get in touch, visit https://ewspconsultancy.com.