Effective microorganisms, or EM, have been experimented & used with good results to significantly reduce odor and pathogens around compost piles, in ponds or some farm animals cages. To make the BSF compost bin odor-free, we can apply some of these EM or microbial enzymes.

What is EM briefly?

EM are the microbes that help break down organic matter while still retaining most of their starting nutritional value. The microbes do this bio-conversion in a dark, cool & anaerobic environment–sort of like fermenting. Most of these beneficial bacteria are those like yeast, lactic acid bacteria or photosynthetic bacteria:

  • Lactobacillus
  • Bacillus
  • Saccharomyces

Compared to the traditional way of composting which could reach 105F (40C), composting with some added EM gives off almost no heat (cold composting). Because of this, much more nutrients is retained in the final compost. As less energy is used, it is also a lot more efficient. When the compost is done, it will be broken down into smaller pieces of amino acids or enzymes that can be taken up directly by the plant roots.

The time to get a compost bin with EM done is usually 4 weeks. Combined with black soldier fly larvae, this process could be reduced to only 15 days. The end result has a light, acidic smell that's totally bearable & doesn't stink. This starter culture can also be used to make a second generation EM2. The liquid from this compost can be collected & sprayed around cages to reduce smell or used as a plant fertilizer.

Make & use your own EM

You can buy ready-made EM online and multiply it or make your own using the kitchen scraps or food waste around.

The 1:3:10 ratio method

This ratio means 1 part sugar: 3 parts waste : 10 parts water. It works for many types of organic waste. For example, we can mix:

  • 1 kg molasses
  • 3 kg food waste
  • 10 liters of water

The food waste are the house of our little microbe army. The molasses or some other types of sugar will be the food source for them to eat and multiply. Water helps us collect the microbes in a liquid or enzyme state & helps dissolve the sugar.

Let this mix sit in a bucket for about 2-3 months to 'cultivate' these good microbes. A cool, dry place is good for their growth. Also, it's advisable to use water without chlorine like distilled water or water from a well. Because the chlorine in tap water can kill the little microorganisms. Shredding or chopping up the foods make it a bit faster for the little guys & girls to digest.

During this process, it may bubble up or release CO2 gas quite strongly for the first few days. Remember to loosen the lid a bit to let the gas out. Make sure the lid has a good seal so houseflies won't come & lay eggs there. After it's done, the juice that we get is the live EM with millions & billions of beneficial microbes. It's quite acidic, noticeable by the sour or acidic smell, which makes it hard for pathogens or other lifeforms to live and flourish, except for the bacteria's own species.

To use this juice, you can mix a 1:200, 1:500 or 1:1000 ratio with water. For example, mix 1 teaspoon of EM for 1 gallon of water. Use this to spray around your BSF compost bin. The active microbes will crowd out & dominate the pathogens. The odor, which usually lingers around, will now be reduced. Pests or houseflies will buzz around less often. In more fancy terms, it's something people call competitive exclusion.

Rice water

You can also collect good microbes using rice water. Soak the rice in water till it turns cloudy. Then, leave it in shade for several days. When it turns a more clear, we can get some of that liquid & pour it into some milk. The clear liquid now contains lots of the little guys we want. And when we add them to milk, it creates a food source for them to multiply.

Some other notes

To really activate or kick start the vigorous growth of the microbes, you can mix in some wheat bran or rice bran. The starch in these things are like the bait to attract the little creatures. Over time, these will also be the food source for their development.

To store your EM liquid culture, avoid direct sunlight or freezing temperatures. Some Lactobacillus specie like the L.casei Shirota will go into hibernation in temperatures about 5-10C (41-50F), meaning, they are still alive but just in sleep mode. When they're put in an environment around 37C (98.6F), they'll be awake & get to work again. A wine refrigerator around the 50s F is perfect for storing these for long use. Too hot or freezing temps may kill them.

Have a great compost

Thanks to the discovery & research of EM by Dr Teruo Higa in the late 1990s, much of the problem with the foul smell of garbage waste, the space to bury waste or the energy input used has been solved quite beautifully.

Kudos to him & a lot more people who are actually applying these ideas in their gardens. Some have turned nearly zero-waste by composting their own stuff. Have a great compost pile with BSF and EM, and enjoy your greens & veggies! Thank God nobody is stopping us now from composting because of the smelly smell.

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