What you need to know:
- Before growing the crop, one must prepare ridges of about one feet high. This helps the tubers to grow bigger.
- One harvests up to a kilo per vine thus from a quarter acre, the yields can hit three tonnes. A kilo of the produce goes from Sh80 to Sh100.
- John Oluoch, a freelance agronomist, says purple-fleshed sweet potatoes do not necessarily require fertiliser to grow.
- One should watch out for diseases such as leaf and stem blight, black rot – which affects the tubers – as well as fusarium root and stem rot.
Sometime back, Wambui Kiragu visited a restaurant in Berlin, Germany, and she was surprised to find orange-fleshed sweet potato fries on the menu.
This opened her mind and upon returning home, where she was farming on telephone, she vowed to give it a try.
“Besides the eye-opening experience in Germany, my entry into sweet potato farming was driven by my quest to get a solution to the challenges I had faced as a telephone farmer, having started farming in 2014. I had tried onion, watermelon and capsicum growing and faced several challenges, including disease attack and lack of water,” she recounts.
Wambui was thus in need of a crop that required little chemicals, was not labour-intensive and did not need much water. Sweet potatoes fitted this bill, narrates the farmer, who grows purple and orange-fleshed sweet potatoes in Makuyu, Murang’a County, on a section of a two-acre family land.
To start the venture, the farmer sourced vines from the Kenya Plant Health Inspectorate Services (Kephis) last year.
Clean, disease-free vines
“Clean, disease-free vines cost Sh10 apiece. A quarter-acre takes 3,000 vines thus I spent Sh30,000,” says Wambui, a 1998 Kenyatta University environmental management graduate.
Before growing the crop, one must prepare ridges of about one feet high. This helps the tubers to grow bigger.
“The ridges should be a metre apart. The planting spacing between one vine and another is a foot,” says Wambui, who works a as a researcher in food systems and sustainable agriculture.
One harvests up to a kilo per vine thus from a quarter acre, the yields can hit three tonnes. A kilo of the produce goes from Sh80 to Sh100.
Wambui sells her produce in her neighbourhood in Nairobi.
“There is great market in neighbourhood WhatsApp groups. I also sell my produce via Facebook under the name Sara Murimi and supply to clients along Kiambu Road, Ruaka, Runda, Waiyaki Way and Lang’ata Road thanks to good courier services.”
Currently, she says she cannot meet demand for the purple-fleshed sweet potatoes.
"This variety has aroused a lot of interest among Kenyans due to its colour and sweetness,” adds the farmer, who currently has one part-time employee.
She advises those who would like to venture into sweet potato farming to do market research.
“From my experience, with more Kenyans going back to traditional foods, you will not go wrong with sweet potatoes. The purple-fleshed is a good bet, especially from nutrition side,” she says.
Watch out for diseases
Wambui has started to add value to her produce. “The chips market needs an alternative raw material and sweet potato offers the best option. Though not on big scale, I process fresh-cut chips for restaurants and events such as weddings. I also make crisps,” she says. Other products she also makes are sweet potato puree or flour for baking.
John Oluoch, a freelance agronomist, says purple-fleshed sweet potatoes do not necessarily require fertiliser to grow.
“If there is too much nitrogen in the soil, it makes the vines grow rather than the tubers,” he says.
He adds that purple-fleshed sweet potatoes do well in hot weather, and take four months to mature and harvest.
One should watch out for diseases such as leaf and stem blight, black rot – which affects the tubers – as well as fusarium root and stem rot.