Vermicomposting: The tiny worms transforming Kenyan farms

In Kiambu in Kenya, a humble unit is helping make healthy soil.

It's a facility for making compost using worms.

Workers sieve the soil, separating redworms from the other matter.

It's these little creatures that are the secret to success.

They are voracious eaters, and when added to waste and livestock dung will chomp through the contents, aerating the beds and producing compost that's pH-balanced and pathogen-free.

It's what is known as vermicomposting.

The venture was founded by George Muturi who started trials in 2018 to transform agricultural waste into compost for the soil.

"When we talk about vermicomposting, we are just talking of using the worms, the earthworms initially reproduced to turn any agricultural or organic waste into an organic fertilizer that we call vermicompost," he says.

Today, his Comfort Worms and Insects farm rears redworms and harvests 12 tonnes of vermicompost each month.

He uses some on his own plots and sells the rest to farmers in need of alternatives to synthetic chemicals.

Muturi's operation taps into Kenya's growing circular economy, where waste becomes wealth.

"There is a huge difference between now the vermicompost out of this process and the cow dung or even the sheep or goat manure out there in terms of their nutrient composition, pH balance, the organic matter, the carbon nitrogen level. All these have a huge difference and also in terms of how safe is my manure when I'm using it on the farm. Because now worms act as cleaning agents in one way. So if there are some pathogens or harmful elements in your manure, the worms will be able to break that down and give us now a very clean and good compost for the soil," he says.

Decades of chemical fertilizer overuse have stripped soils bare.

Organic carbon levels have plummeted in many farmlands, with research showing that roughly 75% of Kenya’s soils experience depleted organic carbon, according to a 2025 report by Heinrich Boell Foundation.

Soil degradation affects 64% of arable land, according to a 2023 World Bank assessment, fueling erosion, compaction and yield drops of up to 50% in key regions like the Rift Valley and Central Kenya.

Farmers across these regions are feeling the pinch firsthand, with many now turning to solutions like vermicompost to restore their land and boost long-term productivity.

Farmers like James Wairuri are converts.

"When I was using conventional fertilizers, it had a lot of chemicals that destroyed the soil but when I started using the organic compost, I noticed that the soil health was improving and my produce increased as well," Wairuri says.

Experts back the buzz.

Speranzer Muthoni, an agronomist at the Rural Health and Environmental Awareness (RHEA) group, highlights vermicomposting's soil-saving perks.

"It addresses the challenge of low organic carbon. It also helps in nutrition, it adds some nutrients into the soil. Because now when the worms are feeding, they are feeding (on) the solid waste, the vegetables, you are feeding them with those kitchen waste there. In the process they are turning it into useful soil and that compost helps the soil. Incase there was an issue of compaction, it helps to loosen the soil. So it adds more nutrients and it aerates the soil. "It adds more nutrients and it aerates the soil," she says.

Repairing the soil, one worm at a time.