How city farmer mints over Sh350,000 every month on an acre plot


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Urban farmer Margaret Karanja demonstrates how sukuma wiki (kale) is grown in a multi-storey bag. PHOTO | EMMA NZIOKA | NATION

Mawe Mbili off Kangundo Road in Nairobi’s Ruai area suggests two stones— or rocks —in Kiswahili. While the actual rocks that gave this eastern suburb of Kenya’s capital its name may not be obvious to a visitor, the neighbourhood’s rocky terrain belies presence of a phenomenal agricultural enterprise, whose replication could transform Nairobi County into a net food exporter.

The Saturday Nation team had been waiting at the Ruai Bridge rendezvous for one-and-a-half hours when finally, at noon and amid a threatening downpour, a van with visitors on a mission to see what a small urban plot could produce, arrived.

University of Nairobi soil scientist Nancy Karanja, who had tipped us off on the visitors from Kajiado, led the convoy to her namesake’s farm.

With the gait of one used to receiving similar visitors, Mrs Karanja takes us on a tour of her one-acre plot, the size of your average up-market city estate—Lavington, Loresho or Kitisuru. A plot in up-market Karen measures half to two-and-a-half acres, the latter being the minimum acreage previously allowed.

It is evident that Mrs Karanja wants to finish with us soonest possible to be able to dedicate herself to the visitors, who have come from distant Kajiado to learn from her initiative, hence there are no ceremonies as we move from one production unit to another.

There are 17 Friesian heifers in the zero-grazing unit, 10 of them in milk. They produce 300 litres a day, on average. “I only deal with Friesian because they have a lot of milk,” Mrs Karanja says, adding, “I sell it at Supaloaf”— one of Nairobi’s major bakeries.

Feeding 17 heifers on a small plot must be a challenge, and the question of where she gets their feeds follows. The cows thrive on horticultural waste, which the farmer gets from Jomo Kenyatta International Airport.


A pick-up load at Sh1,000 lasts two days after mixing it with the hay she gets from Narok.

Prof Karanja, whom I had engaged earlier on the waste disposal-food security link, explains that Naivasha and Naro Moru are major horticultural producers. Technically, therefore, the feed comes from far, far away.

“What does not go out, she gets back. That is adding value to waste,” says Prof Karanja, who is the director of Micren—the Microbial Resources Centre and Larmat—Land Resource Management and Agricultural Technology—at the UoN’s Faculty ofAgriculture and Veterinary Sciences. The waste “is very high quality; very high in proteins because there is a lot of legume,” the don explains.

Proximity to the airport makes it easy for Mrs Karanja to get the feed that also nourishes the two dairy goats she started raising recently. “I’ve noticed that goat milk is very nutritious and I want it for my family,” says the mother of three, who ditched her accountancy career in 2008 for farming, which she started with three Friesians.

At Sh38 per litre of milk, the farmer makes Sh11,400 per day from her cows. Put another way, she earns Sh342,000 per month from milk sales.

From three to 17 cattle in a short four years is astounding…but it becomes mind-boggling to a scribe when she says they would be 36—more than twice the number at the time of the interview, if she had not sold others.

“I do Kilimo biashara (agribusiness),” she says. People think urban farming is just a hobby; it is no longer a hobby but a business.”

Given it was Prof Karanja who linked me up with Mrs Karanja, I’m curious about where the don fits in the whole venture.

Although Mrs Karanja interacts more closely with the Ministry of Agriculture, the don says, her interest as a soil scientist is more on nutrients… “harvesting nutrients from waste and returning them to the soil so that we can have sustainableagriculture,” she says.

The farm also has kienyeji (indigenous) chicken, which lay at least 10 eggs every day. “I don’t buy eggs,” Mrs Karanja says. Some of her chickens are from Uganda and are serviced by a cockerel from India.

“We want to breed them and see how it works,” she says. Mrs Karanja’s believes the birds coming from abroad will be more resistant to fowl diseases. The Ugandan breed is perceived to have more meat, and with the hens showing an 80-90 per cent hatching rate, she is onto something big.

The slurry from cow dung and urine is the mainstay of seven greenhouses, which have red capsicum—“it fetches more money that the green variety” —cucumber and cowpea at the time of the visit.


Cowpea is harvested monthly in rotation with the main cash crops. She sells her red capsicum at Sh120 a kilo—a throwaway, Prof Karanja says, since the same costs Sh250 at the local supermarkets. But even at that price, the 200kg she harvests weekly earns her Sh24,000 in seven days.

It takes three months before harvesting, which continues for another five months before the crop is replaced, Mrs Karanja says. “You can do the mathematics,” Prof Karanja quips to underline the hidden wealth in urban farming.

Thanks to the readily available organic fertiliser, which lends a lie to the deafening clamour for genetically modified organisms (GMO) technology as Kenya’s panacea for perennial food insecurity, the crops in the greenhouse are luscious.

“I’ve started building more greenhouses, because in future, this will be my mainstay,” the farmer says.

The vegetables have a ready outlet at the City Park and Village markets, she says, even as she trains her eyes on bigger things—horticultural exports. “That is why we are constructing more greenhouses.”

Apart from providing manure for the greenhouses, the slurry produces energy in the form of cooking gas. “I don’t buy gas,” she says.

“Some people complain that they don’t have space to grow (crops) or build greenhouses.” Just one row of cowpeas, she says, fetches Sh800. “So anybody who says that she cannot do this is a liar,” the farmer says, adding, manure is the secret.

On a moist bed adjacent to the greenhouses are arrowroots (nduma)—and Mrs Karanja asks an assistant to bring two samples from her latest harvest. They are huge, and I struggle to hold back tears, such is my love for nduma. “They grow very nicely here, (yet) before, we only knew that arrowroots grow on a riverbed with a lot of water. It’s a lie; if you just make a moist bed like this one, then you just water it. The moisture remains even for a week.”

He verdict: farming is a very easy way to survive in the city. “Most people say, ‘I don’t have space’; ‘Our area is very rocky’; ‘We can’t grow anything’; ‘What do you with rocks?’

“You remove them, put manure and get your soil. That is what we did. We tell people, ‘You can grow your vegetables like this, and they are very smart. You should not go to the market because even if you have a very small space, you can also have a multi-storey’”.

The latter technology entails filling a 1,000-gauge-heavy-duty-used cement bag with soil and layering it to grow dhania, sukuma wiki and the like. “It is more than enough to feed a family,” Mrs Karanja says.

The farmer has six assistants, who work on shift. She has a fish pond with 2,000 catfish that have been harvested twice and sold locally after achieving one-kilogramme weight. They take six months to mature.

At this point, the rain is falling in earnest and we must go.


 Urban farmer Margaret Karanja demonstrates how sukuma wiki (kale) is grown in a multi-storey bag. PHOTO | EMMA NZIOKA | NATION

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