What Is Biochar?

Biochar is a carbon‑rich material made from organic matter such as wood, crop residues, or plant waste.

It is produced by heating biomass at high temperatures with little or no oxygen, in a process called pyrolysis. This creates a very stable form of carbon with a highly porous structure that can last in soils for hundreds to thousands of years.

Biochar is similar to charcoal, but it is usually made at higher temperatures (typically around 600–1000°C). That higher temperature creates a more stable carbon structure and a vastly greater internal surface area, making biochar much more effective as a soil amendment than ordinary charcoal.

The history of biochar and Terra Preta

Biochar’s origins go back more than 2,000 years to the Amazon Basin.

Indigenous communities there created extremely fertile black soils known as Terra Preta (“black earth”) by burying and slowly burning organic waste such as food scraps, manure, bones, and charcoal in pits. Over time, this created deep, dark, nutrient‑rich soils that remain highly fertile even today.

When scientists studied Terra Preta in the 20th century, they found that the charcoal in the soil played a key role in holding nutrients, supporting beneficial microbes, and maintaining long‑term fertility. Modern biochar is inspired by this ancient practice.

How biochar is made (pyrolysis explained)

Biochar is made by heating organic material in a low‑oxygen environment so it does not burn to ash.

In simple terms:

Organic material (such as untreated wood or plant waste) is loaded into a kiln or reactor.
The material is heated to high temperatures while oxygen is restricted.
Volatile gases are driven off and can be burned to provide heat or energy.
What remains is biochar: a stable, carbon‑rich, highly porous material.

Modern pyrolysis systems can capture and reuse the heat and gases produced, making biochar production energy efficient and, when made from waste biomass, potentially carbon negative.

Biochar benefits for soil and plants

Biochar acts like a long‑term sponge and habitat in the soil.

Thanks to its vast surface area and porous structure, biochar can:

Hold water and reduce drought stress.
Retain nutrients that might otherwise leach away.
Provide habitat for beneficial soil microbes and fungi.
Improve soil structure, aeration, and drainage.

Because biochar is so stable, these benefits can last for decades or even centuries. Trials and research have shown that biochar can increase plant health and growth by roughly 10–200%, depending on soil type and how it is used.

In many cases, biochar can also reduce the amount of water and fertiliser needed by around 15–40%, while supporting healthier, more resilient plants.

Biochar and carbon sequestration

Plants pull carbon dioxide (CO₂) from the atmosphere as they grow.

Normally, when wood or plant material decomposes or is burned, most of that carbon is released back to the atmosphere. When we turn biomass into biochar instead, much of the carbon is converted into a stable form that resists decay.

When biochar is added to soil:

Carbon is locked away for hundreds to thousands of years.
Soil health improves at the same time.

This process is called carbon sequestration. Because of its potential to store carbon while improving soils, biochar is recognised by the Intergovernmental Panel on Climate Change (IPCC) as a Negative Emission Technology (NET).

How to use biochar in the garden

Biochar works best when it is charged (also called inoculated or activated) before it goes into the soil.

Fresh biochar is very absorbent. If you add it raw, it can temporarily soak up nutrients from the surrounding soil. Charging fills its pores with nutrients and microbes first, so plants benefit immediately.

You can charge biochar by mixing it with:

Finished compost
Well‑rotted manure
Worm castings
Liquid feeds, compost tea, or organic fertiliser solutions

Let the mix sit for a few days to a few weeks so the biochar can absorb nutrients and microbes.

Then you can:

Mix charged biochar into garden beds and borders.
Blend it into potting mixes for containers and houseplants.
Add it to raised beds or no‑dig beds.
Incorporate it into compost systems to reduce odours and improve compost quality.

Typical use rates are often in the range of 5–10% biochar by volume in potting mixes or a light dressing worked into the topsoil, but you can adjust based on your soil and plants.

Used correctly, biochar can:

Improve plant health and yields.
Reduce watering needs.
Cut fertiliser requirements.
Build long‑term soil fertility.

Buy organic biochar for gardening

Make biochar at home using our smokeless kiln

We’re committed to sustainability. Our biochar is made from wood which was destined for landfill or incineration. In addition, we use pyrolysis kilns to create our biochar which utilise smoke to power the process whilst creating carbon neutral heat, making production carbon negative.

To buy our organic biochar, click here. Alternatively find out how you can make your own at home utilising our domestic smokeless kiln.