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What to check before you buy biochar in the UK

Updated: October 2026

You are on amazon.co.uk with a bag that says biochar, a price between £7.99 and £33.98 in this set, and a title that may say 1 litre or 10 litres. What should be clear before you pay is whether the litres match the grams, whether anyone has told you to charge the char, and whether feedstock or a certificate is actually printed. This checklist is for that decision. The [biochar comparison](/hub/fertiliser-soil-and-bark-mulch/biochar) holds the eight listings in one table. A qualifying purchase through our links can earn a commission at no extra cost to you.

You are on amazon.co.uk with a bag that says biochar, a price between £7.99 and £33.98 in this set, and a title that may say 1 litre or 10 litres.

Our top picks

McMillan McMillan Biochar 10L

Best overall

McMillan McMillan Biochar 10L
5.4/10about £26.95
View offer
Invigortex Black Gold Activated Biochar Soil Amendment (1 Litre)

Rank 2

Invigortex Black Gold Activated Biochar Soil Amendment (1 Litre)
7.6/10about £7.99
View offer
Invigortex EarthCraft Blends Bio Char Soil Improver for Plants (40 Litre)

Preis-Tipp

Invigortex EarthCraft Blends Bio Char Soil Improver for Plants (40 Litre)
7.1/10about £33.98
View offer
On this page
  1. 1.What a UK biochar listing should show
  2. 2.Litres that do not match the grams
  3. 3.Activated, organic, and certified
  4. 4.A retail bag or a waste load
  5. 5.What is enough before you pay

What a UK biochar listing should show

A useful listing names the job size, the charge status, the volume and the weight, the feedstock if the seller knows it, and any certificate with a number you can check. Alkaline char, which the RHS describes as pH over 7, is a poor match where you do not want the soil sweeter, including ericaceous plants. None of the eight bags in this comparison print a pH. Only McMillan's 10 litre listing (B0DBRNBWMD, £26.95) says pure wood. No kept ASIN shows a European Biochar Certificate class, a Soil Association number, an NPK, or a PAH result. A 1 litre bag at £7.99 is a few pots. A 10 or 40 litre bag is a compost mix or a small bed, not an allotment plot.

Litres that do not match the grams

Stop comparing price per litre when the title and the weight contradict each other. The Potting Pantry listing (B0H7K9HZ1C) is £16.95. The title says 10 litres and activated. The model number is TPP-BIOCHAR-1L, the unit count is 280 g and the item weight is 310 g. Black Gold prints 1 kg on the 1, 3 and 5 litre ASINs. The 1 litre volume field matches a 1,000 ml unit count. The 5 litre volume field is blank.
McMillan McMillan Biochar 10L

Testsieger

McMillan McMillan Biochar 10L
5.4/10about £26.95
View offer

Activated, organic, and certified

'Activated' in this set is a title word, not a method you can reconstruct. The Potting Pantry bullets still tell you to mix the char with compost, worm castings, liquid feed or nutrient-rich water before planting. Black Gold says activated and does not print a separate charging step. EarthCraft does not say activated at all. If the bag is silent, assume you still have a charging job. The how to use biochar page keeps the rates attached to the people who published them. The European Biochar Certificate is voluntary in the UK. None of these eight ASINs mention EBC.

A retail bag or a waste load

A sealed shop bag is not the same paperwork as waste-code biochar. In England, Regulatory Position Statement RPS 366 (26 February 2026) covers storing and spreading biochar that is waste code 19 01 18. It expects a U10 or U11 exemption, a nutrient need, at most 1 tonne per hectare in 12 months, and distances of 10 metres from a watercourse and 50 metres from a spring, well or borehole. That position applies in England. It should not be copied onto a 5 litre retail pouch sold as a finished improver. LRWP 60 is an operator position for pyrolysis equipment. It is not permission for a garden kiln.

What is enough before you pay

For a normal amazon.co.uk bag, the checks above are enough: job size, charge line, litres versus kilograms, named facts, and whether reviewers describe dust you can live with.

Common questions

What should be on the label before I pay?
You want a volume and a weight that describe the same pack, a line on whether to charge the char, and the feedstock if the seller claims to know it. A certificate only counts if the number or the scheme is on that listing. In this set only McMillan says pure wood, and none of the eight ASINs print a pH, an NPK or an EBC class. If those fields are blank, treat them as unknown rather than as a pass.
Is 'organic' a certification?
Not on these pages. Black Gold's bullets say organic additive and McMillan says slow-release organic fertiliser, without a certifier. Carbon Gold states Soil Association certification for its own enriched improver, and that sentence does not move across to an amazon.co.uk listing that merely uses the word. Great Britain and Northern Ireland also follow different organic regimes, so a holding that must stay certified should ask its certifier before a new input goes on the soil.
Why do two 10 litre bags weigh 1 kg and 4 kg?
EarthCraft's 10 litre listing weighs 1.05 kg at £16.99. McMillan's 10 litre listing weighs 4 kg at £26.95 and says pure wood. Earthly's own char is described at about 0.2 kg per litre, between those two. Bulk density is not stable across brands, so a lower price per litre can be a lighter, finer grade rather than a better deal. The Potting Pantry title says 10 litres beside a 280 g unit count, which is a conflict, not a third density.
Does 'activated' mean I can skip charging?
Only if the listing says the char is already charged and does not then tell you to charge it. The Potting Pantry title says activated and the bullets still say to mix it with compost, worm castings, liquid feed or nutrient-rich water first. Black Gold says activated and prints no separate step. EarthCraft does not use the word. When the bag is silent, plan to charge plain char before you rely on it to hold nutrients.
When is a bulk load a waste question rather than a shop question?
When someone offers you biochar as waste, or you plan to make char from waste wood, read England's RPS 366 or ask SEPA, Natural Resources Wales or the NIEA for the nation you are in. A household 1 to 40 litre retail bag sold as a soil improver is the shop question this page answers. Do not register a waste exemption because a 5 litre pouch arrived from amazon.co.uk.

Related pages

Best biochar for a garden

Biochar or compost

Biochar

Biochar for pots and houseplants, and how much to mix

How to use biochar in compost, pots and garden beds

Sources

Public UK sources from the research digest, used for this page in October 2026. Prices, stars and review counts are from the eight amazon.co.uk listings in this set, captured for the 19 October 2026 scoring pass. No kept bag shows an EBC class, a Soil Association number, a pH or an NPK. RPS 366 is an England position for waste-code biochar, not a household rule for Scotland, Wales or Northern Ireland.

  1. RHS, biochar (retrieved 19 October 2026)
  2. GOV.UK, RPS 366 storing and spreading biochar (retrieved 19 October 2026)
  3. GOV.UK, LRWP 60 making biochar from waste (retrieved 19 October 2026)
  4. GOV.UK, check if your material is waste (retrieved 19 October 2026)
  5. legislation.gov.uk, PFC 3 soil improver (retrieved 19 October 2026)
  6. European Biochar Certificate (retrieved 19 October 2026)
  7. Carbon Gold soil improver (retrieved 19 October 2026)
  8. SoilFixer, biochar application rates (retrieved 19 October 2026)