FAQ
Whether you’re new to biochar or already using SoilFixer products, this page brings together answers to the questions we get asked most often.
You’ll find everything from quick facts about biochar, peat-free gardening and sustainability, to more detailed explanations about how our products work, what they’re made from, and how to use them for best results.
If you can’t find what you’re looking for, feel free to contact us. Our team is always happy to help.
Key Questions About Biochar and SoilFixer Products
What is biochar?
Biochar is a carbon-rich material made by heating wood or plant matter in the absence of oxygen. It improves soil structure, boosts nutrient retention and locks carbon in the soil for centuries, helping plants grow stronger and reducing your carbon footprint.
What are SoilFixer products made from?
All SoilFixer products are made from 100% natural materials, all locally sourced from within 25 miles of our farm.
Are SoilFixer products peat-free?
Yes. Every SoilFixer product is completely peat-free, protecting natural peatlands and supporting sustainable gardening.
Is biochar sustainable?
Yes – biochar turns sustainably sourced woodchip into a stable carbon sink, supports soil productivity and microbes, and is made in a renewable energy system called pyrolysis.
How do SoilFixer products help the environment?
They increase soil organic matter, reduce erosion and nutrient run-off, and store carbon underground – offsetting CO₂ and improving long-term soil health.
How do I use biochar-based products?
Mix biochar into the root zone when planting or use as a top dressing. For faster results, blend it with compost or soak it in a liquid fertiliser to “activate” it before use.
How much biochar should I use?
We recommend 15% biochar mixed with 85% compost as the correct amount.
Where can I buy SoilFixer products?
All SoilFixer products are available through our online store and selected UK retailers and distributors.
How long do SoilFixer products last in soil?
Biochar and colloidal humus are extremely stable and can remain active in soil for decades or even centuries, providing lasting benefits.
Is biochar the same as charcoal?
No, not exactly. Biochar is pyrolysed at 600 °C and is not optimised for fuel value, but for porosity, surface area and chemical stability in soils. Charcoal is made at a higher temperature, designed to drive off volatile compounds and maximise fixed carbon content for efficient burning.
Additional Questions and Environmental Details
Who founded SoilFixer?
SoilFixer was founded by soil enthusiast Tony Callaghan in 2016. In 2025, it was acquired by Brodie Biomass, led by Tom Brodie, with Tony remaining involved as an advisor.
What makes SoilFixer eco-friendly?
We follow nature’s own processes using only natural, renewable materials – biochar, compost and humus – to restore soil health without chemicals or peat.
Is biochar the same as charcoal?
No. Charcoal is made for burning as fuel; biochar is produced cleanly and specifically for soil improvement and carbon capture.
What is colloidal humus?
Colloidal humus is a stable form of organic matter that acts like a sponge, holding water and nutrients for plants. It also locks carbon into the soil for 10 to 100 years.
Can SoilFixer replace chemical fertilisers?
Not directly, but it reduces the need for them by improving nutrient storage and microbial life. Used with compost or natural feeds, it supports a balanced soil ecosystem.
Are SoilFixer products safe for acid-loving plants?
Yes, but use smaller amounts. Most biochars are slightly alkaline, so monitor the pH and keep it between 5 and 6.5 for ericaceous plants like blueberries.
What does “natural” mean for SoilFixer?
It means everything we use is derived directly from nature – wood, compost, humus and biochar – with no synthetic or chemical additives.
What does “sustainable” mean for SoilFixer?
It means we source materials responsibly, use energy-efficient production, and design packaging and logistics to minimise environmental impact.
What is a carbon sink?
A carbon sink captures and stores carbon dioxide instead of releasing it into the atmosphere. Biochar and humus both act as natural carbon sinks.
Why does SoilFixer use plastic sacks instead of paper?
Biochar absorbs moisture and breaks paper bags quickly. Durable woven polypropylene sacks prevent leaks, protect against damp, and keep deliveries clean.
Can I recycle the packaging?
Yes. Cardboard boxes are fully recyclable or compostable; remove the brown plastic tape before recycling. Polypropylene sacks can be reused or recycled where facilities allow.
Does SoilFixer plan to improve packaging materials?
Yes. We’re testing stronger compostable and recyclable alternatives but must balance durability with environmental performance.
What’s SoilFixer’s stance on “greenwashing”?
We’re against it. Sustainability claims must be backed by evidence, and we’re transparent about our materials, processes and carbon-reduction goals.
Can I use SoilFixer in organic gardens?
Yes – our products align with organic gardening principles even though they’re not yet certified under a formal organic scheme.