Activating EM-1: how to make your own EM-A step by step (ratios, temperature, pH)

Print

EM-1 is a stock solution: a concentrate of dormant micro-organisms, designed to be « woken up » before use. By fermenting it with molasses and water, you obtain around twenty times its volume of EM-A, the active solution that is then diluted for the garden, the compost or the home. It is simple and economical, and above all it calls for cleanliness, warmth and a little patience.

Here is the step-by-step method, along with the signs that tell you whether your activation has worked. Instructions sometimes differ: each time, we tell you which figure we go by.

What you will need

• EM-1 Stock Solution, within its use-by date.
• Molasses: this is what feeds the micro-organisms during activation. Cane or beet molasses, it makes no difference: our beet molasses from the Béarn and our sugar cane molasses, both pure and additive-free, play exactly the same role as a source of sugars.
• Non-chlorinated water: clean rainwater, spring water, or tap water left uncovered in an open container for 24 hours so that the chlorine evaporates.
• A food-grade plastic container, very clean, with a cap that seals well. Ideally, use a lid fitted with a valve (or airlock) that lets gas out without letting air in. Avoid glass: fermentation produces gas and builds up pressure. For 10 litres or more, or to activate even in winter, an activation tank such as our EM Activator brings everything together: airlock, heating and tap (see below).
• A thermometer and pH paper, to check the temperature and the result. Our pH test strips (scale of 1 to 14) show whether your EM-A is around 3 or already at 4 or above; to read 3.8 to one decimal place, you need narrow-range paper (roughly 2 to 5) or a pH meter.

Rinse the container with very hot water, without bleach or disinfectant: the slightest residue can compromise fermentation.

The ratios

The standard recipe is the same from the manufacturer of our EM-1 and from other licensed producers: 5% EM-1, 5% molasses and 90% water, that is 1 part EM-1, 1 part molasses and 18 parts water.

• For 1 litre: 50 ml EM-1, 50 ml molasses, 900 ml water.
• For 2 litres: 100 ml EM-1, 100 ml molasses, 1.8 litres water.
• For 5 litres: 250 ml EM-1, 250 ml molasses, 4.5 litres water.
• For 10 litres: 500 ml EM-1, 500 ml molasses, 9 litres water.
• For 20 litres: 1 litre EM-1, 1 litre molasses, 18 litres water.

Some European producers offer a variant with 3% EM-1 and 3% molasses, fermented at a higher temperature (32 to 37 °C) in a heated fermenter. It works too, but we recommend sticking with the 5% recipe, which is more forgiving, with or without a heated tank.

Only make as much as you will use within 1 to 2 months: EM-A does not keep indefinitely.

Step-by-step preparation

1. Warm part of the water and dissolve the molasses in it: being very thick, it does not mix well when cold.
2. Pour this mixture into the container, top up with the rest of the water, then check the temperature: aim for lukewarm water, around 30 °C, never hot to the touch.
3. Add the EM-1 last, once the water is no longer hot, and stir gently.
4. Fill the container almost to the brim, leaving just a small space for gas: the less air left inside, the better.
5. Close it and write the date on the container.

Emy's tip

Use a marker to write on the container the date of preparation and the use-by date two months later. That way you will always know at a glance where your EM-A stands.

Fermentation temperature and time

Warmth is the factor that matters most. The manufacturer of our EM-1 recommends a constant temperature of 25 to 30 °C for one week. Other technical data sheets state that below about 17 °C, activation takes well over 7 days. Frost, for its part, kills the micro-organisms, both during activation and in storage.

Temperature fluctuations are as much of a problem as cold. So find a warm, stable spot: near a radiator (not on it), in a boiler room, on a seedling heat mat, or in a heated room in winter. Wrapping a blanket around the container helps keep the warmth in. A heated activation tank solves the problem: it keeps the mixture at around 30 °C, even in winter. Avoid direct sunlight, and do not exceed 40 °C, which can damage the micro-organisms.

Allow 7 days in good conditions, and up to 10 days, or even a little longer, in a cooler room.

Releasing gas without letting air in

From the second or third day, fermentation produces carbon dioxide: the container swells slightly. This is a sign that everything is getting off to a good start.

• With a valve, there is nothing to do: the gas escapes on its own.
• Without a valve, unscrew the cap a quarter turn, just long enough to let the gas out, then close it again straight away. Once a day is enough at first, then every two or three days.

Do not shake it, do not open it wide and do not taste it: every bit of air that gets in encourages unwanted micro-organisms.

Activating large volumes with an activation tank

Beyond a few litres, or if your home is cool in winter, an activation tank makes everything easier. Our EM Activator, made by Agriton like our EM-1, combines three features:

• An airlock (water seal): the fermentation gas escapes on its own and no air gets in. No more releasing gas by hand.
• Built-in heating, which keeps the mixture at around 30 °C, whatever the season.
• A tap at the bottom of the tank, so you can draw off the EM-A without opening it.

The recipe stays the same: 5% EM-1, 5% molasses and 90% non-chlorinated water.

• 10-litre tank: 0.5 litre EM-1, 0.5 litre molasses, 9 litres water. Enough for a vegetable garden and a household compost heap.
• 30- and 60-litre tanks: 1.5 litres EM-1, 1.5 litres molasses and 27 litres water, or 3, 3 and 54 litres. For large gardens, market gardeners and small livestock keepers.
• 120- and 220-litre tanks: 6, 6 and 108 litres, or 11, 11 and 198 litres. For farms.

Choose the size according to what you will use in one to two months: EM-A from a tank keeps no longer than EM-A made in a container.

Fill the tank halfway with hot non-chlorinated water and dissolve the molasses in it. Top up with cold water to get a lukewarm mixture, then add the EM-1 and stir. Close the tank, fill the airlock halfway with water and switch on the heater, which must always remain fully submerged. After about 7 days, check the pH as described below. Switch off, let it cool, then draw off the EM-A into clean containers, filled to the brim and tightly closed. Never put the heater under cold water while it is still hot.

Emy's tip

Keep the tank out of the sun, in a room between 15 and 25 °C, standing on a piece of cardboard and wrapped in a blanket in winter: the heater will use less energy. In summer, a room that is too warm can push the mixture above 40 °C. Between batches, rinse the tank with hot water and a little white vinegar or citric acid.

How to tell when it is ready

From day 7 onwards, check three things:

• The pH: this is the most reliable indicator. A drop on the pH paper should read 3.8 or below, ideally between 3.2 and 3.6. Above 4, fermentation has not finished or has gone wrong.
• The smell: sweet and sour, pleasant, rather like a fruity vinegar or a mild sauerkraut.
• The colour: the initial dark brown turns to a lighter, orangey brown.

A light film or whitish flakes on the surface are normal: these are yeasts. A pH slightly below 3.2, with a good smell, is not a problem. If the pH stays above 4 after 7 days but the smell is good, leave it somewhere warm for a few more days and measure again. On the other hand, a rotten or sewage-like smell means it has failed: all the signs and remedies are covered in detail in our guide Storing EM and diagnosing a failed EM-A.

Key points

A successful activation means three green lights: a pH of 3.8 or below, a sweet-and-sour smell and a colour that lightens. If in doubt, the pH has the final say.

Diluting and using your EM-A

EM-A is very acidic: never use it neat on living plants. The basic dilution is 1 in 100, that is 10 ml per litre of non-chlorinated water, or 100 ml for a 10-litre watering can. The doses for each use (soil, seedlings, compost) are set out in our guides Using EM in the vegetable garden and Speeding up your compost with EM. For other uses, always follow the product label.

Use it within 1 to 2 months of activation. Counts carried out on an activated solution have shown that lactic acid bacteria decline markedly within a few weeks: the sooner you use it, the better. Keep it cool, out of the light and tightly closed.

If you would rather skip activation, EM-A Microferm Active Solution is ready to dilute. Its flexible pouch packaging (Bag-in-Box) protects it from air, giving it a much longer shelf life than home-made EM-A.

Frequently asked questions

Can I use sugar instead of molasses?

One manufacturer's data sheet allows it, but we advise against it: as well as sugars, molasses provides minerals that are useful to the micro-organisms. If you run out, buy more molasses rather than improvising: it is the standard ingredient in every set of instructions.

Can I make more EM-A from EM-A?

No. The manufacturers are clear: you activate only once, from the stock solution. If you propagate from EM-A, the balance between the micro-organisms drifts from one generation to the next, and you no longer know what you are multiplying. Always start again from EM-1.

Can I use EM-1 without activating it?

Yes, some instructions suggest diluting it directly. But activation multiplies the volume by around 20: for regular use, it is far more economical.

What about making fermented bran?

Bokashi bran is made directly with EM-1 and molasses, without going through EM-A. Our full recipe is in the guide Making your own home-made bokashi activator.

Did you know?

The gas that makes the container swell is mainly carbon dioxide, produced by yeasts, just as in rising bread dough. That is why a container that « bulges » in the first few days is actually a good sign.

In summary

To activate EM-1, mix 5% EM-1, 5% molasses and 90% non-chlorinated water in a clean container filled almost to the brim, then leave it to ferment for about a week at 25-30 °C, at a stable temperature, releasing gas without letting air in. The EM-A is ready when its pH is 3.8 or below, with a sweet-and-sour smell and a colour that lightens. Always dilute it, at 1 in 100 for plants, use it within 1 to 2 months, and start again from the stock solution for each new batch. For large volumes or a cool winter, a heated activation tank maintains the right temperature and releases gas by itself. To get off to a good start with EM, take another look at our golden rules.

Related products

Best Seller

EM-1 mother solution of effective microorganisms | 250 ml bottle

250ml, 1 and 10 litre bottles

£9.48 €11.36

Beet molasses | 250 ml bottle

Animal nutrition or to activate EM (A+), from 250 ml to 10 litres

£3.71 €4.45

Other topics in the guide

Vermicomposting30 sheets →Composting25 sheets →Bokashi24 sheets →