Nairobi — In Ongata Rongai, a peri-urban settlement about 20 kilometres south of Nairobi, beads of sweat form on Moses Koech's brow as he tends tomato plants inside his 240-square-metre wood and polythene greenhouse. "The temperatures are quite high here, but in the morning it is usually cool," said the farmer who spent Sh150,000 to set up the greenhouse.
And for his sweat, he earns considerably more than other area farmers whose sun- scorched plots lie barren. Mr Koech is using farming technology that is spreading fast among small-scale farmers near urban centres and which offers an environment in which temperature, humidity and pests are easier to control.
He grows tomatoes, cucumbers, carrots and capsicum, high value crops in high demand in nearby Nairobi. He sells a kilo of tomatoes in the market for Sh50. The combination of a dry spell, an increase in food prices and growing demand from an expanding urban population has prompted Mr Koech and other farmers to take up small-scale greenhouse farming.
Mr Koech set up his greenhouse in May after visiting the Africa Gospel Church where he saw crops thriving in a controlled environment. Laban Kariuki, a farmer in nearby Kiserian, is happy with his new greenhouse. "Greenhouse agriculture is the best way of getting returns and is not labour intensive. I look at this as business," said Mr Kariuki.
While Mr Koech harvests 100kg of capsicum and similar amounts of tomatoes twice a week, Mr Kariuki harvests double that in his two 240-square feet greenhouses. The farmers' proximity to a major market is a huge benefit, according to Dr Said Silim, the director of Eastern and Southern Africa at the International Crop Research Institute for the Semi-Arid Tropics (Icrisat).
Although the technology has been is use for years in Kabete, it is relatively new in Ongata Rongai, Kitengela and Kiserian where the greenhouses often compete for space with regular houses. A spot check by the Sunday Nation established that dozens of mini-greenhouses have sprung up in these areas in the last eight months.
It costs between Sh100,000-300,000, including installation of drip irrigation pipes, to build a mini-greenhouse on about an eighth of an acre. This new crop of farmers is producing significant amounts of horticultural crops each week with tomatoes, capsicum (green peppers) and cucumber being the most common.
"Tomatoes and capsicum have high value in a short time. They are indeterminate - they can grow tall and have a large surface for fruit development," said Dr Lusike Wasilwa, an assistant director in charge of horticulture and industrial crops at the Kenya Research Agricultural Institute.
So rapid has been the mini-green revolution in the area that Maasai pastoralists in Kiserian, Kitengela and Ongata Rongai are concerned that the greenhouses are taking up vital grazing land and blocking traditional routes. David Nkedianye, a researcher at the International Livestock Research Institute (ILRI) in Kabete, said greenhouses are threatening to edge the pastroalists out of their traditional lands.
"The water issue is a very controversial one. How do you extract so much water for greenhouse agriculture in an arid area where one of the key concerns is water for people and their livestock?" he asked. The pastoralists have been losing up to one-third of their herds in the current drought as they are forced to move long distances to find water.
And securing the necessary amount of water is proving to be a challenge to the new greenhouse farmers. But Dr Silim said farmers who operate greenhouses are able to manage crop diseases and water use; their main concern is temperature which has to be maintained at 24 degrees Celsius for tomatoes, spinach and carrots.
Although they use rainwater from reservoirs to irrigate their crops, Mr Koech and Mr Kariuki often pump water from boreholes to supplement the supply. While fertilisers are a major concern to farmers elsewhere in the country, most small greenhouses require only a small amount of what experts say should be 100g per square metre.
Early last month, the Horticultural Crops Development Authority (HCDA) launched a campaign to introduce greenhouse technology in western Kenya. It has yet to catch on, which is attributed to the high initial set-up cost of up to Sh300,000.
Farmers in other parts of the country like Nyandarua, Bungoma, Machakos, Bomet, Kitale and Narok are gradually embracing the greenhouse technology. Experts from HCDA say tomato farming in greenhouses is suitable to areas such as Nairobi, Kiambu and Kisii where plots are small and the crops performs poorly under traditional open conditions.
Dr Wasilwa of Kari said crops in a greenhouse can thrive in any place, even in hot and dry conditions. In places with high temperatures farmers have to use insect-proof screens. But there are concerns that many mini- greenhouse farmers do not have access to the appropriate information to help them manage water, fertilizers and pests.
For instance, not every tomato variety is recommended for a greenhouse. Kari is conducting research to develop varieties of tomatoes for greenhouse agriculture and to determine the type of manure to be applied. Dr Wasilwa said contrary to using the recommended one hour of drip irrigation a day, many farmers flood their greenhouses with water.
"Drip irrigation in a greenhouse is efficient because the water is sprinkled to the roots and it helps to manage weeds. Some farmers are flooding the greenhouses, which is not good. They should keep them wet to avoid soil-borne diseases. They should keep the soil moist but not let it get waterlogged," he said.
And although diseases are generally manageable in a greenhouse, he said, pests are still a major problem. But fungal diseases don't affect greenhouse crops as much as those grown in the open air. "For fungal diseases to thrive they require water to germinate and infect the plant. In a greenhouse, because of the heat, the water dries up quickly," said Dr Wasilwa. "That's why, with greenhouse agriculture, diseases among capsicum and tomato has decreased."
Gilad Millo of Amiran Kenya, an Israeli horticultural firm, said the company sells a farmer's kit for Sh139,600. The greenhouse costs an additional Sh94,500. "Approximately 40 kits have been sold in the Nairobi area, together with an additional 25 greenhouses, making the total number of greenhouses 65," he said.
A farmer could install an Amiran farmer's kit with up to four greenhouses, all irrigated from the same drip," said Mr Millo, whose company has imported the Israeli technology.