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EM-1 or Microferm

Updated: 23 October 2026

The two jerrycans sit next to each other on amazon.co.uk. EM-1 or Microferm is a stage question before it is a size question. EM-1 is dormant mother culture you activate with molasses. Microferm is already active liquid you only dilute. Brew the stock if you will keep a warm airtight jar. Buy Microferm if you want to dilute this weekend. The [effective microorganisms comparison](/hub/diy-supplies/effective-microorganisms) lists the packs and the badges. Peter F. used the Moutta Farm pages and the amazon.co.uk captures. We did not run a jar. A qualifying purchase through our links can earn a commission at no extra cost to you.

The two jerrycans sit next to each other on amazon.co.uk. EM-1 or Microferm is a stage question before it is a size question. EM-1 is dormant mother culture you activate with molasses.

Our top picks

Moutta Microferm 5 litre ready liquid

Best overall

Moutta Microferm 5 litre ready liquid
7.5/10about £44.90
View offer
Moutta Microferm 2 litre ready liquid

Alternative

Moutta Microferm 2 litre ready liquid
7.5/10about £27.99
View offer
Moutta EM-1 1 litre stock

Rank 3

Moutta EM-1 1 litre stock
7.8/10about £39
View offer
On this page
  1. 1.Stock versus already active
  2. 2.The price only works if the brew works
  3. 3.Which one to take home
  4. 4.How long each liquid keeps

Stock versus already active

Moutta's EM-1 page says the stock is dormant until you activate it, and that Microferm is already fermented, so you dilute it. The titles say stock solution and ready-to-use. The 1 litre file also prints a mixing ratio of 1:10, which UK activation pages do not use for the brew. Actiferm is a UK shop name for a ready liquid in the same job as Microferm. It is not an ASIN in this set. No file here prints a MAPP number, and the Health and Safety Executive treats a pest or disease claim as a different legal object from a soil-life claim. The organisms sellers describe are lactic acid bacteria, yeasts, and phototrophic bacteria, at two stages. Sizes sit on the best effective microorganisms page. BioBizz Microbes, the 150 g powder, is neither of these liquids.

The price only works if the brew works

A rule of thumb, not a measured yield from these canisters: 1 litre of EM-1 at £39, brewed at 5 percent to about 20 litres, lands near £1.95 per litre of activated liquid before you buy molasses. The 5 litre Microferm is about £8.98 per litre in the bottle. The stock looks cheaper on the garden after a successful brew, and only then. A spoiled jar, from chlorine or sulphured molasses, erases the gap. Dr Forest says to use a finished brew within about 30 days. The 10 litre stock is about £30 per litre of concentrate and about 200 litres of brew. Microferm's clock is the carton. Moutta describes the bag-in-box as keeping up to a year after production. These amazon files print no use-by date. The recipe stays on the how to activate EM-1 page.
Moutta Microferm 5 litre ready liquid

Testsieger

Moutta Microferm 5 litre ready liquid
7.5/10about £44.90
View offer

Which one to take home

Take the 1 litre EM-1 home when you will run an airtight brew, use the liquid within about 30 days, and you want the lower cost per litre after that brew succeeds. It is the top pick for a finishable concentrate, at £39. Take the 5 litre Microferm when you will not brew this month and you will use 5 litres. Take the 2 litre at £27.99 when £44.90 is too much at once. Leave the 10 litre until you already know the brew. Leave both liquids if you need a pesticide, a pet treatment, or a stated fish medicine. Those answers are not in the files. If the brew fails twice, stop treating the £1.95 figure as your price and buy the ready liquid.

How long each liquid keeps

Dr Forest's window for a finished EM-1 brew is about 30 days. Moutta describes Microferm in a bag-in-box as keeping up to a year after production. The amazon files print no use-by date. The mother culture in the sealed canister is a different clock from the brew you make later. A pond line on a seller sheet is not a fish-safety test.

Common questions

What is the actual difference?
EM-1 is dormant stock you activate with unsulphured molasses and dechlorinated water for about a week. Microferm is already active liquid you dilute. The 1:10 field on the 1 litre file is not the activation recipe the UK brew pages use.
Which is cheaper once I have brewed?
As a rule of thumb, 1 litre of EM-1 at £39 makes about 20 litres of brew, near £1.95 a litre before molasses. The 5 litre Microferm is about £8.98 a litre in the bottle, and the 2 litre about £14. The gap exists only after a sweet-sour brew you use within about 30 days. A spoiled jar removes it.
What if the brew fails?
You have spent the stock, the molasses, and a week, and you have no liquid for the beds. Chlorine and sulphured molasses are the failures UK sellers name. Discard a rotten batch. For the next month, the 2 litre or 5 litre Microferm does not depend on the jar.
Do I activate Microferm?
The titles say ready-to-use, and the files do not print a molasses brew. Dilute from the seller sheet. Moutta's unretested figure for plants is about 1 percent. Activating Microferm as if it were EM-1 is a step those pages do not ask for.
Is Actiferm a third product I must buy?
Actiferm is a UK shop name for a ready liquid in the same job as Microferm, with shelf-life claims of about a year in some bag-in-box descriptions. It is not an ASIN in this set. Buy it only if that shop is where you are paying. Disease claims on some of those pages are not repeated here.
Can I use either on a pond?
The Microferm bullets mention silt, and one German review says the buyer uses the 5 litre on a pond. Moutta prints a seller rate of about 1 litre per 1,000 litres of water over a year, which was not retested here. There is no fish-safety line and no MAPP number. Do not treat either bottle as a fish medicine.

Related pages

Effective microorganisms buying guide

Effective microorganisms

Best effective microorganisms for soil and compost

Bokashi effective microorganisms: bran, not a bottle

How to activate EM-1 mother culture in a sealed jar

Sources

Public UK sources and the amazon.co.uk listings compared on this page. Updated 22.10.2026.

  1. HSE: Biostimulants (retrieved 22.10.2026)
  2. HSE: Biopesticides (retrieved 22.10.2026)
  3. Regulation (EU) 2019/1009, Annex I (retrieved 22.10.2026)
  4. The Fertilising Products Regulations 2020 (retrieved 22.10.2026)
  5. RHS: Bokashi composting (retrieved 22.10.2026)
  6. Agriton UK: EM-1 (retrieved 22.10.2026)
  7. Moutta Farm UK: EM-1 mother solution (retrieved 22.10.2026)
  8. BioBizz: Microbes (retrieved 22.10.2026)