One stem, two plants for more tomato yields

Saturday July 7 2018

Paul Mwangi, attends to tomato crops inside one of his two greenhouses in Mukuria Village of Kandara in Murang'a County.

Paul Mwangi, attends to tomato crops inside one of his two greenhouses in Mukuria Village of Kandara in Murang'a County. He uses double-stem technology to grow the tomatoes. PHOTO | BRIAN OKINDA | NMG 

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The weather is drizzly as the Seeds of Gold team navigates its way into Mukuria, a sleepy hamlet in Kandara, Murang’a County.

Tea is the mainstay of residents as the crop covers the expanse of the countryside, spreading as far as the eyes can see.

Our destination is Paul Mwangi’s farm, where he grows tomatoes, propagating them using double-stem technology for higher yields.

“I learnt the technology from the internet and I have perfected it over the years. It enables me get double yields from a single tomato plant,” offers Mwangi, who studied computer engineering at Nairobi Institute of Business Studies, and completed in 2013.

Mwangi says he begins by buying certified seeds from the agrovet. Thereafter, he plants the seeds in trays and when they reach the size to transplant, he nips the plant’s tip.

“This enables it develop side shoots, leading to formation of two or more main stems,” he says.

He later transfers the plant inside pots in a greenhouse where he grows them. “I normally remain with two suckers on a single plant and prune the other. The advantage of growing more stems is that it translates to more tomato yields from a single plant.”

The plants grow and when they reach maturity, each yields fruits as independent plantlets despite all developing from a single plant.

“From a limited space, and just from one seedling, one harvests more tomatoes, depending on how well they manage the crops, nutrition and protection from pests and diseases,” says Mwangi, who invested Sh350,000 when starting.

Mwangi has two greenhouses measuring 8 by 15m each, which he bought on second-hand, and grows his tomatoes in pots.

“I harvest five crates of tomatoes every week when the crops mature. If I was using the normal system, I would end up with three,” says the farmer who is in his mid-20s and has been using the technology for seven months.

Other than marketing snags, his biggest challenge initially was pests and diseases.

When he started, bacterial wilt, fusarium wilt, root rot and blight and pests such leaf-miner ravaged his crop. And due to the costly nature of testing and treating soils, he had to device means to ensure his agribusiness thrives.

“To overcome the bacterial wilt problem, I was advised to go for virgin soil. I ‘imported’ soil from an unused patch of land, which had for long remained forested and experienced little human activities,” he says.


He ferried the soil into the greenhouses, then mixed it with manure and filled it into the planting bags. All this while he maintained zero contact between the ‘imported’ soil and the soil in the greenhouses.

He then made wooden beds where he placed the pots filled with soil.

“The idea was to ensure the soil in the bags and that inside the green do not mix. This further minimises contact between the plants and the soil in the greenhouse, and enables the water to spread throughout the bags.”

He waters the plants using drip irrigation system, with a drip for each planting bag. “I get the water from a small water pan that I dug and put dam liner at the bottom. So far, I have been able to overcome diseases and pests, thanks to the technology,” says the farmer, who worked at a construction site and flower firm in Nakuru before finding his footing in tomato farming.

After planting the tomatoes, for the first one-and-a-half months, he waters them once per day but after that, until they mature, he does it thrice.

He uses soluble fertiliser that he applies through the drip irrigation system.

“This way, I minimise wastage of the fertiliser as the drip only gives the plants the amount they require at any time, during each of their stages of growth,” says Mwangi, who propagates twin stem/twin head tomato seedlings for sale at Sh15 each.

He sells his harvest to local hotels, schools and hospitals at Sh80 per kilo.

“After transplanting, use phosphorus-based dissolved fertiliser which is good for the tomatoes’ root development. Later, introduce standard soluble fertiliser for their quick and optimum growth until when the plants near flowering. Then shift to potassium-rich fertiliser for the tomatoes’ big size development and good colour,” he advises.

Mathew Dida, a professor of plant breeding at Maseno University, points out that twin-stemming is an effective way of boosting one’s yields especially in instances where one has limited land like in greenhouses.

The technology helps in breaking the apical dominance in the plant ensuring its side branches, which are usually the more numerous, thrive and in effect, from a single plant, one is able to get more fruits.

“Cultivation in the greenhouse minimises the likelihood of attacks from pests particularly Tuta absoluta, and diseases such as the different blights, fusarium and wilts,” says Dida, adding the use of virgin soils in instances where one cannot afford soil treatment, to an extent helps to keep tomato pests and diseases at bay.