By Rabecca Mwila

Are you tired of spending your money on expensive chemical fertilisers that degrade your soil year after year?

There is a better way, and it starts with what you already have: cow dung, ash, molasses and clean water.

Farmers at the Kasisi Agricultural Training Centre (KATC) in Zambia have developed a simple, low-cost method to make fermented liquid bio-fertiliser (FLBF). A nutrient-rich, microbe-packed alternative that boosts plant growth, improves soil health and costs almost nothing.

The exciting thing is that you can make it yourself using locally available materials.

Here is exactly how, step by step.

Why Use Fermented Liquid Bio-Fertiliser?

•  Saves money: No need to buy synthetic fertilisers.
•  Builds healthy soil: Adds beneficial bacteria and fungi that feed plants naturally.
•  Improves yields: Supports stronger roots, greener leaves and better harvests.
•  Eco-friendly: No chemical runoff, no pollution, just natural cycles.

What You Will Need

Gather these materials before you begin:

• 1 sack (50 kg) of fresh cow dung
• 4 kg wood ash
• 4 litres molasses (or dilute 1 kg brown sugar in 4 litres water)
• 4 litres of milk or whey
• 500 grams yeast
• 180 litres of clean, chlorine-free water
• 2 kg mineral salts (optional)
• 1 x 200-litre plastic drum (airtight lid)
• 1 small mixing container (20+ litres)
• Transparent hose pipe (1 metre long, 1 – 1.25 cm diameter)
• 1 empty 1 – 2 litre plastic water bottle
• Irrigation coupling + jubilee clip
• Wooden stick for stirring
• Plastic glue & rubber stopper

Important: Use only clean, non-chlorinated water (rainwater or well water works best). Chlorine kills the good microbes needed for fermentation.

Step 1: Prepare an Airtight Fermentation Drum

Fermentation only works without oxygen. So, your drum must be sealed tightly.

1. Drill a small hole in the centre of the drum lid.
2. Insert the hose pipe through the hole.
3. Seal around the pipe with plastic glue to prevent air leaks.
4. Attach a rubber valve or stopper to the inside end of the pipe.
5. Connect the outside end to a plastic water bottle (this will act as an airlock).

How the airlock works: As fermentation happens, gas builds up and bubbles out through the water bottle, but no air can enter back into the drum. This keeps the process anaerobic (oxygen-free), which is essential for good fermentation.

Step 2: Mix Manure and Ash

1. Pour 100 litres of clean water into the 200-litre drum.
2. Add the 50 kg sack of fresh cow dung.
3. Add 4 kg of wood ash.
4. Stir well with a wooden stick until fully mixed.

Tip: Fresh dung is key; it contains live microbes that kickstart fermentation.

Step 3: Add Molasses, Milk and Yeast Mixture

In a separate container:

1. Mix 10 litres of clean water.
2. Add 4 litres of molasses (or sugar water) and 4 litres of milk or whey.
3. Stir well.
4. Add 500 grams of yeast and mix again.
5. Pour this mixture into the main drum and stir thoroughly.

Step 4: Top Up and Seal

1. Add more clean water until the drum reaches the 180-litre mark.
2. Seal the lid tightly.
3. Place the drum in a shady, dry spot away from direct sun and rain.
4. Ideal temperature: 38 – 40°C (like a cow’s stomach!).

Step 5: Let It Ferment

• Wait 3 – 4 weeks in warm weather.
• In colder areas, it may take 8 – 12 weeks.

How to know it is working?

Watch the water bottle: bubbles mean fermentation is active.

How to know it is ready?

• Smells like alcohol or sweet vinegar
• Has a reddish-brown, slightly transparent colour
• Shows foam on top

Do NOT use if:

• It smells rotten
• The surface is green, black, or mouldy
• The liquid is cloudy with blue/green streaks

This means air got in, and harmful bacteria may have grown.

Once opened, the drum cannot be resealed. Use the liquid within a few days.

Step 6: How to Apply the Bio-Fertiliser

1. Dilute: Mix 1 litre of FLBF with 20 litres of water.
2. Use a knapsack sprayer or watering can.
3. For row crops (maize, beans): Spray along the base at a rate of 1 metre per second.
4. For station-planted crops: Use 1 cup (300 ml) per planting station.
5. Apply every 2–3 weeks as a top dressing.

Best time to apply: Early morning or late afternoon, avoid midday sun.

Safety Tips

• Always wash your hands after handling the mixture.
• Wear old clothes or gloves (e.g., cut-up sugar bags).
• Use a cloth over your nose and mouth when mixing or spraying.
• Store unused FLBF in a cool, shaded place and label it clearly.

Why This Matters for the Future of Farming

Chemical fertilisers drain farmers’ incomes and degrade soils over time. However,  fermented liquid bio-fertiliser turns waste into wealth using resources already on your farm. 

When combined with other agroecological practices such as botanical pest sprays (mtetezga, chisoyo) and crop diversification, you build a resilient, profitable and sovereign farming system.

Download the Full Guide: How to Make & Use Fermented Liquid Bio-Fertilisers – KATC Poster

Image Caption: Fermented Liquid Bio-fertiliser made during the Kasisi Agricultural Training Centre Field Day.

Credit: KATC