Once dismissed as wild weeds and a “poor man’s food”, indigenous leafy vegetables in Kenya are now becoming much more common – grown on farms, sold in markets and gracing the menus of restaurants.

At the busy Skinners Restaurant in Gachie just outside the capital, Nairobi, one employee says demand for “kienyeji” – as all local vegetable varieties are known – is higher than for other greens.

“Many people ask for kienyeji when they come here,” Kimani Ng’ang’a tells the BBC, despite the fact the restaurant charges extra for them as he says they are harder to source.

Vegetables like cabbage, spinach, kale and spring greens, introduced by colonial authorities before the 1960s, are more readily available and cheaper. Spring greens are known as “sukumawiki”, meaning “stretch the week” in Swahili, reflecting how they have become a daily staple.

But diners in Gachie are part of the growing wave of Kenyans who see the benefits of eating local, organically produced nutrient-rich varieties of greens.

“It detoxifies the body and is good in weight loss,” says James Wathiru, who ordered “managu” – or African nightshade.

Another person told me: “It’s all about its taste, which is better.”

According to horticulture professor Mary Abukutsa-Onyango, this trend is reflected in government data and some of the health benefits are backed by research.

Over the last 10 years, production of local greens has doubled – with 300,000 tonnes produced by local farmers last year, she says.

It is a remarkable change in attitudes, given people used to look down on traditional crops as inferior – not realising they were often more resistant to diseases and pests, meaning they can be grown organically.

In the 1980s, when Prof Abukutsa-Onyango began her studies, she says she was perplexed to find them referred to as “weeds”.

“We never learnt about African indigenous vegetables. They were calling amaranth ‘pigweed’ [and] spider plant, they were calling it ‘spider weed’,” she tells the BBC.

Her postgraduate research on traditional plants was also tricky as there was no literature about them, but she persevered and now works with the government to promote them for food security.

She says managu and other local vegetables like “mrenda” (jute mallow) and “terere” (amaranth) have more essential minerals than sukumawiki, as well as “higher levels of vitamin A and C [and] antioxidants” that boost immunity and reduce the risk of disease.

Some varieties also contain protein, making them an excellent option for vegetarians. She notes for instance that 100g (3.5 ounces) of mrenda – known for its distinctive slimy texture when cooked – contains more nutrients than a similar portion of common cabbage.

The progress people like Prof Abukutsa-Onyango have made in promoting the diversity and knowledge of indigenous vegetables was acknowledged by Unesco in 2021, when the UN cultural agency commended the East African nation for the “safeguarding of intangible cultural heritage” that had been threatened by “historical factors and the pressures of modern lifestyles”.

It noted that Kenya had begun a project in 2007 involving scientists and local communities to record an inventory of traditional foods, which now includes 850 indigenous plants and their local names.

Some of these vegetables are eaten nationwide, while others are specific to certain areas or communities.

But sukumawiki, first introduced to Kenya from the Mediterranean as animal feed, is still favoured by many farmers – with more than 700,000 tonnes produced in 2023 – more than double the volume of all indigenous leafy vegetables combined.

Francis Ngiri, who used to farm in Kirinyaga in central Kenya where cabbages are a mainstay crop, explains that this is because, especially during the 1970s, those growing imported leafy vegetables used fertilisers and pesticides that damaged the local biodiversity.

Today, he tells the BBC, only the introduced varieties thrive as the soil has become too acidic to support many native species.

Determined to do something so they would not be lost forever, Mr Ngiri moved his operation to Kenya’s Rift Valley – an area he considers relatively untouched by chemical contamination – so he could practise organic farming of indigenous crops.

On a four-acre (1.6 hectare) farm in Elementaita, he began with 14 native varieties in 2016. Today that has grown to 124, many of which he has sourced through seed exchanges with fellow farmers. His farm now draws visitors from across Kenya and neighbouring countries.

They come to see how he collaborates with 800 other regional farmers, who also grow organic food for local markets, to preserve and regenerate “forgotten plants”, ensuring their genetic diversity is safeguarded for future generations.

Nonetheless by swapping seeds, Mr Ngiri and his colleagues are actually breaking the law as the government only allows the planting of certified seeds.

This controversial law was introduced in 2012 with the intention of protecting farmers from purchasing poor quality seeds.

Wambui Wakahiu, who trains farmers on seed conservation, says such policies do not support efforts to save indigenous crop varieties, as their seeds are not available in farm-supply shops.

She works for Seed Savers Network, a non-governmental organisation with 400,000 members, which helps establish seed banks for farmers to safely store and preserve their local seeds.

Her team found that more than 35 traditional plant varieties had been “completely lost” in one county alone because of the law.

“If [the farmers] focus more on the exotic [foreign] seeds, then the traditional seeds continue going away. And we have seen most of them go extinct,” she tells the BBC.

Mr Ngiri and others who have been exchanging seeds have not been pursued by the authorities, but he says the law does prevent them from marketing them: “If I can’t sell the seed, I don’t own it.”

And getting certification is a rigorous, costly process, as seeds need to be tested in a laboratory for their purity and things like how well they germinate.

Dr Peterson Wambugu, a chief research scientist with the national gene bank at the Kenya Agricultural and Livestock Research Organization (Kalro), acknowledges that under the current law, the exchanging and sale of uncertified seeds – including those saved by farmers – is criminalised.

However, he points out that this is at odds with the International Treaty on Plant Genetic Resources for Food and Agriculture, of which Kenya is a signatory, as it sets out farmers’ rights to save, use and exchange their seeds.

The national gene bank has been working with other groups to draft regulations through the agriculture ministry to align Kenyan law with the treaty.

The proposals, once passed by parliament, will allow farmers to exchange their seeds “without fearing that what they are doing is criminal”, he tells the BBC.

However, the selling of such seeds would still remain outlawed – something Dr Wambugu knows means the journey to full acceptance of indigenous crops continues.

For Priscilla Njeri, a vegetable vendor in the bustling Wangige market in Kiambu county just outside Nairobi, there is no turning back, as she can see first-hand that indigenous greens are now the most popular with her customers – something she puts down to the media campaigns that promote them.

“The most preferred are managu, terere and kanzira [African kale] – which is popular for those who have sensitive stomachs as it has no gas,” she tells the BBC.

“But all the kienyeji greens are good because they have a better taste.”