Soil Fixer Biochar Granules (0-13mm)

Approx. 20% <2 mm

Approx. 50% 2–8 mm

Approx. 30% 8–13 mm

Trommel sieves may allow a few long, thin bits to pass, so some particles may slightly exceed 13 mm.

We do not recommend using fine biochar powder (amorphous biochar) because it lacks the macro-pores needed by soil microbes. We also advise against using very large granules (>13 mm), as they offer low pore surface area and can negatively affect soil aggregation (tilth).

Read more in our biochar blog.

How Much Biochar Should I Apply?

Apply 1 kg per square metre (1 kg/m²)

This is roughly equal to 5% by volume, although it depends on soil depth.

For more information on how to calculate by area, volume or weight – and how to stretch your biochar budget – see our application ratio blog.

Volumes and Weights

Biochar naturally absorbs water, and moisture content varies with the seasons. That’s why we sell by volume (litres) and provide an approximate weight.

20 litres ≈ 10 kg

40 litres ≈ 20 kg

Our product contains approximately 40% water by weight.

If comparing prices across suppliers, make sure you’re comparing volume (litres) or adjusting prices to reflect £/kg of dry biochar.

FAQs

Is biochar safe for vegetables and edible plants? Yes. SoilFixer biochar is Soil Association approved and European Biochar Certificate certified, making it completely safe for vegetable gardens and edible crops.

How long does biochar last in the soil? Biochar is extremely stable and can last hundreds to thousands of years in soil. It’s a permanent soil improvement, not a short-term fertiliser.

When is the best time to apply biochar granules? Biochar can be applied at any time of year. Autumn and spring are ideal — autumn allows it to settle over winter, spring gives immediate benefit for the growing season.

What is the difference between 0-8mm and 0-13mm granules? The 0-13mm coarse grade is ideal for borders, trees, shrubs and larger garden beds. For pots, seed beds and lawns, use the 0-8mm fine grade instead.

All bags have been decanted from bulk bags into clear/plain plastic bags.