Lactic Acid Bacteria (LAB) is a powerful microbial solution made by fermenting milk with cultured starchy water.
It’s used to strengthen plant and soil microbiomes, suppress pathogens, accelerate decomposition, and even improve human and animal gut health. Its versatility and simplicity make it a valuable and beginner-friendly KNF input.
Check out our video if you are a visual learner!
Get the printable recipe by signing up below!
How to Make LAB
Traditionally developed by Master Cho, this simple recipe yields a simple but powerful plant spray to keep your garden healthy.
Ingredients
- White rice or other starchy grain (uncooked)
- Water (non-chlorinated)
- Whole milk (not “plant-milk”; animal milk contains the lactose that is digested and converted by the bacteria)
- Optional: sugar for preservation
Equipment Needed
- Non-metallic jar or container
- Breathable cover (e.g. paper towel or cheesecloth with rubber band)
Step-by-Step Instructions
- Collect starch water
- Add 1 cup starchy grain to a bowl with just enough water to cover. Mix vigorously for 60 seconds to release starch. Strain out the grain (you can cook it later) and reserve the milky water.
- Ferment the grain-wash water
- Pour into a glass jar or non-metal container.
- Cover with a breathable lid. Let sit in a shaded, warm spot (65–85°F/18-30°C) for 2–3 days.
- It should develop a slightly sweet-sour smell and may form a white film on the surface of the liquid.
- Discard and restart if any colorful mold (green, blue, black, red) appears.
- Ferment with milk
- Pour the fermented starchy water into a container of whole milk (rough ratio: 1 part starchy water to 10 parts milk).
- Cover loosely with a breathable lid.
- Let sit in a warm, shaded area for 3–7 days.
- You’ll see three distinct layers when it’s ready:
- Top: white curds (casein)
- Middle: clear yellow serum (this is your LAB)
- Bottom: light sediment
- Harvest the LAB
- Skim off and compost or use the curds for animal feed or press into cheese.
- Carefully pour off the yellowish LAB serum into a clean bottle or jar.
- Preserve your LAB
- You have two storage options:
- Refrigerate, sealed, for 6-12 months.
- Or mix with an equal weight of sugar to make it shelf-stable at room temperature for 6–12 months.
- Keep covered with a breathable lid if ambient temperatures are particularly warm. Otherwise, LAB jars can build up pressure and explode if microbes aren’t fully dormant.
- You have two storage options:
How to Use LAB
Use LAB anytime you apply fertilizers and inputs to your garden. Dilute 1:500 in water to apply to plant foliage (leaves and stems). Apply undiluted (or diluted if you’d like) directly to the soil (before plants go in the ground) or compost piles to stimulate microbial activity.
Get a printable recipe for LAB by accessing our Resource Library below!