Living Compost vs. John Innes: Which Soil Mix Grows Healthier Plants?

If you’ve ever stood in a garden centre staring at shelves of compost, you’ve probably seen bags labelled John Innes No. 1, No. 2, or No. 3. They’re familiar, trusted, and widely recommended.

But what actually is John Innes compost? And how does it compare to living compost, the biologically active soil we produce at Generation Soil?

The difference isn’t just about plant growth. It’s about how soil works, how ecosystems function, and what kind of future we’re growing towards.

What Is John Innes Compost?

John Innes compost is not a single product but a set of standardised soil-based mixes developed in the 1930s by the John Innes Horticultural Institute.

Unlike most bagged composts, John Innes mixes contain:

• Loam (soil)

• Sand or grit

• Peat or peat alternatives

• Synthetic fertilisers

The numbered versions are designed for different growth stages:

• John Innes No. 1 for seedlings and young plants

• John Innes No. 2 for established plants

• John Innes No. 3 for mature plants and shrubs

• John Innes Seed Compost for germination

Their popularity comes from consistency. Every bag behaves the same. But that reliability comes with hidden costs.

The Limits of John Innes Compost

John Innes mixes are designed to feed plants directly, not to build living soil.

They rely on synthetic fertilisers to provide nutrients in fixed doses. This can support short-term growth, but it bypasses the soil food web, the living network of microbes that naturally delivers nutrients to plants.

Over time, this approach can:

• Reduce microbial diversity

• Create fertiliser dependency

• Degrade soil structure

• Increase nutrient runoff into waterways

In many cases, peat is still used, which damages peatlands, one of the planet’s most important carbon stores.

What Makes Living Compost Different?

Living compost works with biology, not around it.

At Generation Soil, we produce compost that is biologically active, meaning it contains thriving communities of bacteria, fungi, protozoa, and other microorganisms that continue working once added to soil.

Here’s how living compost compares.

1. Living Compost Feeds Soil Life, Not Just Plants

John Innes compost delivers nutrients chemically.

Living compost delivers nutrients biologically.

Microorganisms break down organic matter and minerals, making nutrients available to plants gradually and in balance. This process strengthens root systems, improves disease resistance, and builds long-term fertility.

Healthy plants are a side effect of healthy soil.

2. Completely Peat-Free and Climate-Friendly

Many John Innes composts still contain peat or rely on peat substitutes that mimic its structure.

Our living compost is entirely peat-free.

Instead, we use food waste, wood chips, biochar, bokashi fermentation, and natural decomposition. This protects peatlands, reduces carbon emissions, and keeps valuable organic matter in the soil cycle.

3. Circular, Regenerative, and Local

John Innes compost follows a linear model: extract, mix, sell, discard.

Living compost follows a circular one.

At Generation Soil, food waste collected in Bristol is transformed into compost and returned to local gardens, allotments, and growing spaces. In just six months, we diverted over two tonnes of food waste from landfill.

Food becomes soil. Soil grows food. The loop closes.

4. No Synthetic Fertilisers, Ever

John Innes mixes depend on artificial fertilisers for plant nutrition.

Living compost contains none.

Synthetic fertilisers can disrupt soil biology, leach into waterways, and create long-term dependency. Living compost feeds soil organisms instead, which then feed plants naturally and sustainably.

This creates fertility that builds rather than depletes.

5. Supports Biodiversity Above and Below Ground

Soil is not inert. It is a living ecosystem.

Living compost supports fungi, bacteria, earthworms, insects, and plant roots working together. This improves:

• Soil aeration

• Water retention

• Nutrient cycling

• Ecosystem resilience

John Innes compost supports plants.

Living compost supports life.

6. Suitable for Every Grower

Whether you’re growing salad on a windowsill, managing an allotment, or building a market garden, living compost provides a flexible, resilient foundation.

Unlike standard mixes that need constant feeding, living compost keeps working long after it’s applied.

It improves soil year after year.

Which Soil Mix Grows Healthier Plants?

If the goal is fast, predictable growth in pots, John Innes can work.

If the goal is healthy plants, resilient soil, biodiversity, and climate responsibility, living compost is the better choice.

Living compost doesn’t just grow plants.

It grows soil.

Make the Switch to Living Compost

Choosing compost is a choice about the kind of system you want to support.

By using living compost, you are:

• Reducing food waste

• Supporting local soil regeneration

• Protecting peatlands

• Building long-term fertility

Our compost is not just a growing medium. It is a climate solution.

Join us in regenerating soil, food systems, and communities, one compost bin at a time.