For most gardeners, compost is a product you pick up at the garden centre, open the bag , and hope for the best. But after more than 15 years immersed in compost science, biochar, humus formation, and the mechanics of real-world composting, I’ve learned something that most manufacturers, retailers and gardening blogs rarely say out loud:
There is no “one-size-fits-all” multipurpose compost — but there is a way to help gardeners choose the right one.
That belief is what led me to create MultiPurposeCompost.co.uk, a new site built not to sell compost, not to promote brands, but to give gardeners clear, evidence-guided, practical help.
And because the full website isn’t quite ready, this post sits on the AC Innovations blog as the story behind it — a place to explain the “why”, the “who”, and what will make MPC genuinely different when it goes live.
Why I’m Involved: Compost Isn’t the Side Story; It’s the Foundation
My background with compost goes back decades, but things accelerated when I invented the HOTBIN — a system born from frustration that garden composting simply wasn’t working the way it should. That journey sparked years of deep research:
- Why do some composts perform brilliantly and others collapse?
- What actually makes good humus?
- Why do two composts labelled “multipurpose” behave nothing alike?
Along the way, I founded SoilFixer, developed a range of biochar-compost blends, worked through countless windrow trials, analysed many mixes, and eventually created the Callaghan Soil System Model (C-SSM) to make sense of how soil physics, chemistry and biology interact as a whole.
So when I looked at the compost buying landscape — dozens of brands, new peat-free mixes, confusing marketing terms, and wildly inconsistent performance — it was clear that gardeners needed honest, structured, practical guidance.
No more opinions.
No more myths.
No more “Top 10 composts!!” lists.
Something different.
Who’s Helping: A Coalition of Real-World Expertise
Although MPC is my project, I’ve had help from some fantastic people and organisations in shaping the science, the testing, and the structure:
- SoilFixer/Brodie Biomass — access to PAS100 compost, biochar, and practical field trials.
- Experienced growers and long-time HOTBIN users — providing real-world performance data that no lab test ever captures.
- AI tools (including ChatGPT) — helping organise a vast volume of research, create balanced explanations, and build structured templates that simplify complex decision-making.
- Friends in the horticulture community — who have shared mixes, failures, successes, and honest insights about what works.
MPC is designed to be independent — not tied to any brand, not paid to promote products, and not afraid to point out limitations or gaps in data.
Why It’s Different: Balanced Scorecards, Not Hype
Most compost reviews are just opinions.
At MPC, we’re doing something unusual:
Every compost is scored using a structured, transparent Balanced Scorecard.
A scorecard breaks each product into its component realities. Not just NPK or texture, but the deeper attributes that determine how it actually performs:
- Water behaviour (infiltration, drainage, retention)
- Physical structure and longevity
- Biological potential
- Nutrient availability
- Consistency between batches
- Fit-for-purpose performance (seedling, potting, raised beds, containers, top-ups)
- Sustainability and input materials (coir, wood fibre, PAS100, AD fibre, etc.)
Each of these categories uses a consistent narrative band — phrases chosen carefully to be informative, neutral and non-judgemental.
It means two composts might both score well, but for different reasons.
And a gardener reading the review understands why a product works in one scenario but not another.
That nuance is what has been missing for years.
Contextualised Advice, Powered by AI (But Grounded in Soil Science)
MPC isn’t just another library of FAQs.
It’s an advice system designed to contextualise, which is a fancy way of saying:
You ask a question, and the guidance adapts to what you’re trying to do.
Instead of:
“Product X is good.”
You’ll see:
“For containers: strong performer for moisture control, but watch for early nutrient drop-off.”
“For raised beds: excellent structure but may need supplementary feed mid-season.”
This is where AI plays a role.
Not as a replacement for expertise, but as a tool that helps organise, structure and present advice in a way that’s accessible, consistent, and genuinely helpful.
The AI doesn’t “decide” anything.
It simply helps transform years of structured research into guidance that makes sense to gardeners in real situations.
What MPC Will Become
This staging-post blog sits on AC Innovations because the full site is still being built. When it goes live, MPC will deliver:
- The UK’s most structured compost reviews
- Evidence-guided FAQs (not myths, not folklore)
- Clear explanations of feedstocks, additives, biology and structure
- Side-by-side comparisons using consistent scoring
- Practical guidance for different gardening goals
- Updates as peat-free mixes evolve and manufacturers change recipes
It will evolve constantly — because compost evolves constantly.
A Final Word: Compost Doesn’t Need More Noise — It Needs Clarity
MPC exists because gardeners deserve clarity, not confusion.
Because peat-free composts are improving rapidly but inconsistently.
Because the UK needs better information if it’s going to move to sustainable growing media.
And because after a decade and a half in the thick of compost, biochar, soil and humus research, I want to help gardeners avoid the trial-and-error that so many endure.
The full website will go live soon.
This blog is simply the beginning — a place to explain the “why” before we get to the “how”.
If you’d like updates when MPC launches, keep an eye on the AC Innovations site