LAB – lactic acid bacteria I The bouncer of Korean Natural Farming (KNF)

What are lactic acid bacteria actually?

The term lactic acid bacteria is the German translation for Lactic Acid Bacteria. This English term is used internationally in the Korean Natural Farming scene. Lactic acid bacteria can be isolated via fermentation processes and used for garden applications. We will go into more detail about the exact application possibilities in the next chapter, but first let’s look at the structure and taxonomy of the microbes.

LAB are a large group of bacteria and cannot be narrowed down to a single species. They have been used for centuries by many different cultures for fermentation and preservation of foods such as sauerkraut or kimchi. These bacteria survive even the low/acidic PH produced by fermentation, which also allows them to survive our digestive system when consumed. These bacteria are very good for our intestines and help with constipation and keep the microorganism milieu in balance.

LAB in the Gut and its effects
(Source 3)

As if that wasn’t enough, LABs are also responsible for the production of yogurt and cheese, as they form the basis for separating the rennet from the liquid. However, in today’s high-tech production, native rennet strains are no longer used but specially grown cultures. This is because different population compositions also produce the different types of cheese.

What are LAB used for in Korean Natural Farming?

Now we have heard a lot about commercial use, but how does it benefit us now in gardening? Since there are three different purposes, we will make a small separate chapter for each.

Use as a single preparation

Now that we have isolated our LAB serum, we can use it as is. The only thing to keep in mind is to dilute it with water, otherwise it can give off a rather strong odor after application. The rate for this is about 1:1000 with pure, antibiotic-free water. Unfortunately, an exact figure cannot be given here, as each LAB serum is colonized to a different extent.

It can then be sprayed directly onto the soil around the base of the plant. This prevents colonization with harmful bacteria and speeds up the conversion of organic fertilizers. A special advantage that LABs offer is the conversion of sugars to hexanoates (salt of caproic acid = hexanoic acid shown in source 4), which are precursors and building blocks for terpenes. This means that the plant does not have to produce these substances itself, which is energy-intensive, but can use them directly. This saves energy, which can be used again for the production of sugars and other metabolic processes.

Biosynthesis of Cannabinoids and Terpenes
(Source 4)

The next and important point is the use in the phytosanitary field (pest prevention). Again the LABs can shine by being extremely strong and competitive against other microorganisms. As already described in the production, after a certain incubation/propagation time they can take over almost the entire area by claiming the available food (sugar, especially lactose) for themselves.

Not only against other bacteria but also against fungi such as powdery mildew they can successfully assert themselves. This is how the oldschool trick of the milk/water mixture against the uninvited guest came about. However, this is now much more efficient and faster with the help of our LAB serum.

The concentration for this also remains at 1:1000, since the LABs can multiply very quickly, if enough food is available. The whole thing should be applied as a foliar spray by spraying the plant with an atomizer, but take care not to go below a particle size of 5µm, otherwise this will kill the bacteria.

Lactic acid bateria
(Source 5)

The treatment is extremely effective in a protective (preventive) way, but its effectiveness decreases with the severity of the infestation, so it is only partially curative (plant is infested but does not show symptoms yet) and poorly eradicative (strong visible infestation). In case of eradicative planned action, a synthetic fungicide should be resorted to, if it is really absolutely necessary to save this cultivar as in the case of phenotypic selection.

Another point to consider with lactic acid bacteria is their ripening delaying effect, which can give undesirable results especially in the last 2-3 weeks of the flowering phase. From week 3 at the latest week 5 (depending on the duration of cultivar flowering of course) the addition should be stopped, otherwise neither the calyx hairs will turn brown nor the trichomes will mature properly.

Use as compost starter

Now we come to one of the most important point of LAB application: Its role in the initial processes of any compost.

First, we should look at the basic process of lactic acid fermentation, which is an anaerobic (without oxygen) catabolic (degrading) process. Here, glucose is converted to pyruvate and this is converted to lactate (salt of lactic acid) with the help of a coenzyme. This lactate is the starting material for the following decomposition processes, which finally leads to our beloved compost.

Depiction of Lactic acid fermentation and subsequent degradation of Pyruvat


This process can be further divided into homo- and heterofermentative processes, after which the respective bacterial strains are also differentiated.

The first process is the “pure form”, which means that this degradation is pure, i.e. apart from lactate no other by-products are formed (apart from the “used” coenzyme). Although lactate is also acidic, it is much gentler for microbes than acetic acid, thanks to its lower pKA value. Because with a low pKA value, the acid or salt of an acid can interact poorly with the microbial cells.

Heterofermentative fermentation, on the other hand, as you can probably imagine, produces other substances such as acetic acid and ethanol, which are highly toxic to our compost. This can lead to a lowering of the PH levels and the subsequent tilting of the population. You can recognize this at home by a strong smelling compost, which looks rather slimy and structureless than decomposed.

Homo- vs Heterofermentative Metabolism
(Source 6)

The starting point of these microbial conversion processes in compost is almost always started by two different strains of LAB.

The first is “Pediococcus acidilactici” (homofermentative), which accounts for more than half of the bacterial strains grown, this inhibits the synthesis of acetic acid, which in turn is extremely toxic to most auxiliary bacteria.

The second one is “Weissella paramesenteroides” (heterofermentative), which is the counterpart of the above mentioned specimen. This one produces exactly large amounts of acetic acid and slows down the composting process accordingly. This synthesis drastically decreases the PH in the entire colonized area and thus prevents the start of the decomposition process.

Accordingly, one should pay attention to the ratio in which it is applied. In a study of the “the science of total Environment” Magazines a ratio of 10^1,5 was found as optimum.

In this optimal ratio, the lactate blocks the PH reduction by the acetic acid and thus allows the colonization of the rotting raw material with fungi, which can degrade complex organic compounds such as lignin or chitin. The resulting degradation products again form reactants (starting materials) for terpene synthesis and activate systemic (plant internal) pest defense processes such as the formation of R-proteins.

If these fermentation processes are now finished after approx. two days, Paecilomyces species begin with the colonization of the material, the degradation of organic acids (PH increases -> aerobic bacteria settle from approx. Ph=6.5). Thus, the microbial aerobic degradation process can be started.


Combination with other KNF products

In the last part of the application in the horticultural field, the synergetic effect with the other KNF preparations must of course be mentioned. Mostly it is used right from the beginning as part of the Seed-Soak Solution (SSS), an organic solution that optimally prepares the seed for germination.

As mentioned before, LAB can repel competing bacteria or fungi (e.g. Pythium) lurking on the small, weak seedling. The exact mixture of the SSS will be discussed in a separate chapter, but roughly speaking, it is a combination of BRV (brown rice vinegar), FPJ (fermented plant juice), OHN (oriental herbal medicine) and our LAB.

But what are the other preparations for? Good question, because these also bring massive benefits to your sustainable garden. The rice vinegar buffers the PH range around your seeds into the right range so that the formation of anaerobic metabolites (alcohol etc) is suppressed.

The fermented plant sap gives a wide range of beneficial raw materials such as yeast species/hormones/enzymes and nutrients. This little lunch package helps the seed to establish itself quickly and strongly so that it quickly enters the “safe” phase where it can no longer be destroyed by just a small fungus.

Finally, the OHN is added, which together with the LABs plays the bouncer against fungi. The combination of alcohols (very very low concentration, which damages pathogens, but cannot harm our seed) and the active ingredients of ginger, angelica, licorice, garlic and cinnamon makes it almost impossible for pathogens to damage the seedling.


Another important application is the combination with IMO (indigenous microorganisms). Here LAB forms one of the starting materials in the collection of IMO also again with the protective aspect. Because we want strong, composting fungi and not fast-living bacteria.

But also in the preparation of a new soil mixture it can be added together with IMO or Liquid IMO to create a good base and stimulate the nutrient cycle.

Inputs: Tasks: Mixing ratio: Seedling: Vegetative state Flower I (Week 1-4) Flower II (Week 5-8) Flower III (Week 9-10)
OHN Medicine 1:1000 4ml 4ml 4ml 4ml 4ml
BRV Catalysor 1:500 8ml 4ml 8ml 8ml
FPJ Food Veg 1:500 8ml 8ml 8ml
FFJ Food Flower 1:500 8ml 8ml
LAB Starter 1:1000 4ml 4ml
FAA Fuel 1:1000 4ml 4ml
SW Minerals 1:30 120ml 130ml 150ml
WCP Bone builder 1:800 5ml 5ml

How can I grow the LAB myself?

We have now heard about its many uses, but how do we put it into practice?
First, we need some materials:

  • rice
  • A lactose source (milk/milk powder/isolate)
  • Clean water
  • A large glass jar
  • A breathable cover (paper (uncoated)/silk cloth/fabric)
  • Rubber band/thread
  1. First, we soak the rice in water for 48std to filter out the starch. The rice should be completely covered and stirred 4-5 times.
  2. The water is filled into the previously washed jar to about 2/3, covered with the help of the cloth and tightened with the rubber band. This prevents pests from creeping in. It is especially important that the jar does not contain any residues of detergents/vinegar cleaners or similar agents.
  3. Now you can incubate the jar at room temperature out of reach of sunlight for 3-5days. The time varies depending on the temperature and richness of the environment in lactobacilli.
  4. After the waiting time, a semi-solid film should have formed on the surface. Do not worry it is not mold Lactic Acid Bacteria Züchtungsbeginn                (Source 1)
  5. Now you can remove the lid and pour off the water, but be sure to remove the semi-solid part that floats on top.
  6. Then the lactose source, in our case milk, can be mixed with the opaque water in a 10:1 ratio. However, the final glass should still not be more than 2/3 full, otherwise it will overflow.
  7. The jar can now be sealed again as before in a breathable manner and stored. The mixture should now not be shaken during the fermentation phase.
  8. After another 4-6 days the mass should have separated as shown in the picture below. Again, the temperature is crucial, however, 25 ° C should not be exceeded, otherwise it can go bad.
    .              (Source 1)
  9. The yellow liquid is now our LAB serum, which we strain and take great care not to mix it with the solid again.
  10. The mixture should have a slightly sweet smell and if it starts to stink (sour milk), pour it away.
  11. If the serum is to last longer than 3-4 days it must be stored half-open (CO2 is formed) in the refrigerator. For very long storage (3 weeks +) it should be mixed with equal weight of brown sugar so that there is no unbound liquid left. This puts the LAB into a kind of cryo-sleep also called dormancy, where they become active again as soon as enough water is available again.

Can I still use the curd/lab?

The real rennet or curd, which has settled on top, can be removed and eaten. Especially for animals like dogs, pigs and chickens it is very nutritious and helps the digestion by its probiotic effect.
For human consumption, however, it should first be made into cheese, for this there is a super
tutorial video by Chris Trump


Lactobacilli and the human intestinal flora

As already mentioned in the introduction, lactic acid bacteria contribute significantly to intestinal health. Here they keep the balance between acidifying and alkaline acting bacteria. Because by fighting for nutrients, they can outcompete smaller, faster-digesting bacteria. This is good for us, because when bacteria convert nutrients, mostly H+ ions are released, which can lead to a rapid drop in Phs (PH = negative decadic logarithm of H+ concentration). This causes an unbalanced intestinal flora, resulting in digestive problems and even ineffective utilization/absorption of nutrients.

Unpasteurized dairy products contain a lot of lactobacilli, but can also contain pathogens so we would personally advise against it unless you have a microscope and can really differentiate the species.

A good option would be tiny doses of LAB serum (too much can easily lead to unpleasant side effects like diarrhea or abdominal pain). The best alternative in our opinion is to process the “curd” into cheese and eat it. But even here you should pay close attention to the quality, because the curd can sometimes tip over due to the non-sterile production, if it is too warm. This has a similar effect as fermented milk on one so it is not recommended.

But there are many good tutorials on cheese making and ripening with separate microbial strains, so you can easily make your own dream cheese.





  1. Natural Farming: Lactic Acid Bacteria“; David M. Ikeda1 , Eric Weinert, Jr.1 , Kim C.S. Chang1 , Joseph M. McGinn1 , Sherri A. Miller1 Cheyanne Keliihoomalu2 , and Michael W. DuPonte2 1 Cho Global Natural Farming Hawai‘i, Hilo, HI
  2. Lactic acid bacteria modulate organic acid production during early stages of food waste composting“;Quyen Ngoc Minh Tran 1, Hiroshi Mimoto 1, Mitsuhiko Koyama 1, Kiyohiko Nakasaki 2Q
  3. Lactic Acid Bacteria and Bifidobacteria with Potential to Design Natural Biofunctional Health-Promoting Dairy Foods“; Daniel M. Linares1,2, Carolina Gómez1, Erica Renes3, José M. Fresno3, María E. Tornadijo3, R. P. Ross2 and Catherine Stanton1,2*
  4. Complete biosynthesis of cannabinoids and their unnatural analogues in yeast“; Veronica Benites;
  5. The value of Lactic Acid Bacteria in Bees’s stomachs and honey for human medicine“; Mark;
  6. “Biotechnological valorization of agro industrial and household wastes for lactic acid production”;Juliana Romo-Buchelly, María Rodríguez-Torres, Fernando Orozco-Sánchez;