Using Woodchip for Soil Health, Mulching & Composting
- Jane Westoby
- Mar 27
- 3 min read
If you’ve ever wondered whether that pile of woodchip sitting in your garden is worth keeping, this one’s for you.
In this week’s podcast, I’m joined by Ben Raskin, Head of Agroforestry at the Soil Association, author of The Woodchip Handbook, and a passionate advocate for low-intervention, regenerative growing.
We talked all things woodchip—what it is, why it matters, and how to use it to transform your soil health (without digging a thing). As someone who already uses woodchip around my own garden, I knew there was more to the story—but I had no idea how powerful it really was until this conversation.
So What Is Woodchip, Really?
At its simplest, it’s chipped or shredded tree branches. But as Ben explains, not all woodchip is created equal. There’s:
Bark chip – a dry by-product of timber milling, great for paths but low in nutrients.
Mixed woodchip – what most tree surgeons leave behind; a mix of branches, leaves, and trunk.
Ramial woodchip – from young branches under 7cm thick. Nutrient-rich, full of life, and ideal for building soil health.
This young, twiggy woodchip (the kind most of us get from pruning or tree surgery) is absolutely bursting with potential.
“The bark is where all the nutrients are… the more young wood you have, the more useful the chip is—even fresh.” – Ben Raskin
How Woodchip Feeds Your Soil
One of the biggest takeaways from our chat was just how effective woodchip is at building soil life, especially fungi.
Ben explained that most cultivated soils are low in fungi—because fungi hate being disturbed. Woodchip feeds fungal networks, which in turn improve structure, help retain moisture, and make minerals more accessible to plants.
“It’s like fast food for fungi,” Ben says. “All those cut ends in the chip make it easier for fungi to move in and start breaking it down.”
That decomposition process doesn’t just feed fungi—it draws in the whole soil food web: bacteria, nematodes, earthworms, and beyond. It’s slow-release, long-term soil building at its best.
Moisture, Structure & Drought Resilience
Adding woodchip as a mulch doesn’t just build soil health—it also saves you watering.
Ben shared trials showing that mulching with woodchip can reduce watering needs by up to 25%, especially during dry spells. And it’s not just moisture retention. Soils with regular woodchip mulch become more sponge-like: they drain better when it’s wet, and hold onto moisture when it’s dry.
How to Use Woodchip in the Garden
You don’t need to dig it in. In fact—don’t! Just mulch it on top and let nature do the work. Ben recommends using it in three key areas:
Paths – An obvious win. It suppresses weeds and looks great.
Around trees and shrubs – Mulch deep (even 25cm!) for long-term weed control and moisture retention.
In established borders – Perfect for building structure over time.
If you're growing shallow-rooted veg or seedlings, it's best to compost it first or mix with grass clippings or manure to avoid nitrogen lock-up.
Where to Get Woodchip
If you’ve got trees, you’ve got a resource. If not, Ben suggests:
Connect with local tree surgeons – many still pay to dispose of chip.
Try Arbtalk – a site where you can register as a drop-off location.
Ask your allotment association – many organise shared chip deliveries.
Buy in bulk – 1m³ bags are available online, though they can be pricey.
“Any woody growth in your garden is your fertility. If you send it away, you’re losing a free resource.” – Ben Raskin
Want to Learn More?
Ben’s book, The Woodchip Handbook, is packed with real-world case studies, field trials, and surprising uses for woodchip—from propagation compost to disease-resistant mulch. It’s a must-read if you want to take your garden soil to the next level.
🎧 Listen to the Episode
This episode is a brilliant listen—informative, funny, and totally inspiring. I came away with a whole new appreciation for this “waste” material. I think you will too.
👉 [🎙️ Click here to listen now on your favourite podcast app]
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How to Make Nettle Tea Fertiliser – another brilliant, free garden booster.
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