EM: Effective MicroOrganisms

SQWorms does currently have Effective MicroOrganisms (EM) available for order. Anyone wanting some EM; can request an order; or is welcome to cultivate their own, by following recipe’s provided below.



“Effective microorganisms” is a liquid culture of specific “facultative anaerobic” microbes which provide excellent benefits for an organic garden. Facultative anaerobic means microbes which are capable of living in air with oxygen, as well as in low oxygen conditions. They’re also called fermenting microbes and are responsible for making your bread, beer, wine and yogurt.

The 3 microorganism groups are lactic acid bacteria, yeast and photosynthetic bacteria, plus many other wild microbes.

Many people tend to use “effective microorganisms” and “EM” as generic terms to describe many different brands of similar products; however EM and Effective Microorganisms are either registered trademarks or trademarks of EM Research Organization, Inc. in the United States and/or other countries.


What are Effective Microorganisms Used for?

Effective Microorganisms create an abundance of antioxidants, control the breakdown of organic matter, and according to some people, are an extremely positive energy force.

Effective microorganisms were originally developed and used in agriculture to improve compost and soil organic matter breakdown. It was even found to have a beneficial energizing effect on other microbes in the soil. After its results were noticed in soil and composting, EM began to be used in other gardening areas, helping beat diseases such as Botrytis, insects such as weevils, etc..

It is not a pesticide and can’t be marketed as such. It acts more as an immune booster, creating a more healthy plant. It also helps crops achieve higher brix and longer storage. One study reported a 50% increase in yield was obtained just with EM.

Other uses for Effective Microorganisms include:

  • to control odors, diseases and insects on animals
  • to clean polluted water, septic systems and sewers
  • to make bokashi, which can be used to pickle your food scraps
  • an amazing probiotic for humans
  • in deodorant, toothpaste, cleaning, laundry, odor control
  • for garbage dumps, soil remediation, cleaning hospitals, oil spills

Effective Microorganisms, EM, and EM1 are registered trademarks of EM Research Organization in Japan.


Activating Effective Microorganisms

Effective microorganisms can be “activated”, a 3-5 week process (or longer). Add 1 part EM, to 1 part molasses and 20 parts water. This is fermented, for 3 to 5 weeks, which increases your quantity of EM by about 20 times. The activated EM is used in the same way as regular EM.

Dilution Rates for using Effective Microorganisms

Effective microorganisms should be applied in smaller, regular doses, such as monthly or weekly, and can be combined with other biostimulants.

EM is diluted with water for application with ratios from 1:50 water to 1:10000 water. The ratio depends on the frequency of application and the area you are trying to cover, such as for example:

  • 1:10000 – for daily use, such as through an irrigation system
  • 1:1000 – for weekly foliar use; 20-125 ml of EM per 1000 sq ft
  • 1:100-1:250 – for monthly use as a foliar feed;
  • 1:50 – for monthly/seasonal use on turf and as a soil drench
  • 1:1000 – for soaking seeds; 5-10 minutes only, as some seed may ferment after too long

Be careful: it is theoretically possible to ferment flowers and young, tender leaves if the application rate is below 1:250.




  • 1/4 cup rice
  • 1quart Mason Jar
  • 1 cup water
  • 1 fine mesh strainer
  • 80 oz milk depends on how much one is making
  • 1 gallon container or jar
  • 1 tsp. black-strap molasses


1. Place rice and cup of water in mason jar and shake vigorously until water is cloudy white, strain off rice kernels and discard into your compost bin or cook for dinner.

2. Place cap on loosely and store in a cabinet or cool dark place for 5-7 days.


3. Sift off top layer and strain liquid (serum)

4. Measure your rice liquid and now add a ratio of 1 part fermented rice to 10 parts milk. Culture in a large jar, letting it sit sit for 5-7 days.

5. Sift off curd settlement and add to your soil or feed your animals it is good for their digestion, then there should be a light yellow serum left this is your inactivated serum.

6. Refrigerate as is, or you can add 1 tsp molasses to feed and keep your bacteria alive and refrigerate. To store without refrigerating, add 1 part molasses to 1 part serum.

7. To activate microorganism activities, add serum to room temperature non-chlorinated water at a ratio of 1 part Serum to 20 parts water; (or alternatively to make Activated EM in larger quantities, follow Activating EM as above, and in more detail below).

8. Feed to plants either directly to soil or follicular feeding.



Effective Microorganisms (EM) can be activated to multiply your EM by about 20 times the original amount. 

Ingredients (per 1L):  1-1.5 part EM (40ml-60ml) to 1 part Organic Blackstrap Molasses (40ml). Add to 20 parts dechlorinated water (800ml). Chlorinated water will kill the microorganisms. If chlorinated, let it sit for 24 hours to dechlorinate.

Optional Additives:
1/4 tsp ceramic powder to structure the water (more won’t hurt) 
1/2 Tbsp rock dust for minerals 
1/2 tsp sea minerals 
1/2 tsp liquid kelp 
1/2 tsp liquid fish 

1. Heat some of the water to 115-125F 
2. Pour water into your bottle and dissolve molasses 
3. Mix in any of the optional ingredients and then mix in the EM 
4. Add the remaining water and stir and/or shake very well. 
5. Leave 10% air space in bottle 
6. Tighten lid and keep warm (95-110F is optimal) for at least 2-4 weeks
5. After first few days, burp container, to release gasses. Continue burping for the first 3 weeks. 
6. Use once pH is below 3.9, but preferably below 3.7. It should have a sweet smell. 
7. Best benefits if left for at least 4 weeks. If cooler (below 70F), leave for 6-8 weeks.
8. Leave the lid off for the first 24 hours to encourage breathing

1. EM Mother Culture stores for 6-24 months, or potentially a few years, if refrigerated. 
2. Activated EM stores for a month or two, or potentially 2 or more years if it is a good batch. Cooler room temperatures will keep it longer (10-20C is optimal). Store it in the dark, with the lid tight. 
3. While it is good to brew it with a bit of airspace and stir/shake it daily during the first 3 weeks of brewing, it is best to store it after that without any airspace and without any more shaking if you want to keep it stored for more than a month. 

Activating EM Helpful Hints: 
If batch smells bad, or fails to drop in pH to an appropriate level, dump it on your compost heap and start again.
A few common reasons for failure are: 
1. Unclean or contaminated containers 
2. Poor water quality (polluted or chlorinated) 
3. Container too full in initial fermentation stages (best at 90% full) 
4. Bad temperature (too hot or too cold) 
5. Failing to burp and stir/shake daily 
6. Cheating by using more molasses than EM.