Forget grass or twigs, here’s new way to mulch crops

Friday October 28 2016
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Johana Walumbe Wamalwa, an employee at Soil Ripe Ltd in Isinya, Kajiado County, on their bullet chilli farm where they use poly mulch. PHOTO | CAROLINE WAMBUI | NATION MEDIA GROUP


Huge swathes of dry land stretch yonder as one traverses Isinya in Kajiado County, some 60km from Nairobi.

The county is primarily a semi-arid region with numerous challenges that include desert vegetation, inadequate rains and a sunny weather, all which make it rough for both crop and livestock farmers.

But despite the tough conditions, crops are flourishing and livestock is thriving, thanks to innovative farming methods.

One of the places to visit for lessons on successful farming in a dry area is a three-and-a-half acre farm located some 7km from Isinya town along the Namanga Road.

The farm named Soil Ripe Ltd uses plastic (poly) mulch technology to grow tomatoes and capsicum, each on an acre, for the local market.

They also grow bullet chilli on half-acre and African bird’s eye chilli on an acre using the technology for sale in Britain, Germany, Norway and France.


“As the name suggests, this is a technology that helps in mulching, therefore, controls weeds, prevents soil erosion, reduces evaporation and keeps diseases at bay,” says Hilda Wangari, the owner of the farm.

They have been using the technology for the last two years, saving immensely on costs associated with weeding, water use and diseases.

“Our savings while using the technology are about 50 per cent. The plastic mulches are specially designed not to absorb heat which may harm the crops,” explains Wangari, adding the paper imported from China, which cost them Sh300,000, is hard to tear and can serve for at least three years before wearing out.

Farm manager Moses Odhiambo says many farmers use grass for mulching, which while it does the work, it does not guarantee better water retention, especially in semi-arid places like Isinya.


“Plastic mulch technology cuts water use by reducing evaporation, which means the crop gets 100 per cent of the water required. We learnt the technology from Amiran and is widely used in Israel and Asia.”

Through the method, soil erosion is also controlled since the ground is covered and, therefore, no splashing of water occurs. With no splashing, the spread of diseases from one crop to the other is minimised.

“The technology also promotes the right spacing as both the drip and the plastic mulch paper have the right and equal spacing,” says Odhiambo.

To lay out the technology, Odhiambo explains that the land is thoroughly ploughed, turning over the soil followed by harrowing to make the soil texture fine as a good tilth is suitable for seedbed.

Thereafter, uniformly compacted and fertile beds are then created manually or by a tractor, followed by racking then laying down of the drip lines and the mulch paper which is specially designed to match with the drip’s spacing.

“The plastic mulch paper is punched depending on the crop, which dictate distance from one hole to another, but average is 30cm or 45cm. The ground is then wetted awaiting transplanting,” says Wangari.

If planting for the export market, the farm should meet standards that include inspection by Horticultural Crops Development Authority (HCDA), have a farm inspection report, a pack house inspection report, a farmer and exporter’s contract report, an inspection report on transport, receipts on the seeds purchased, have a traceability system and that the farmer export contract be witnessed by a HCDA officer to avoid unsafe produce from reaching the market.

Furthermore, soil and water have to be tested at the Kenya Agricultural and Livestock Research Organisation, which will advise on what to use depending on the acidity level in the soil and water.

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Paul Gaute, an agronomist on the Soil Ripe Ltd's African Bird chilli farm in Isinya, Kajiado County. PHOTO | CAROLINE WAMBUI | NATION MEDIA GROUP

“For us transplanting of chilli seedlings is first done into plastic bags two weeks after germination and later to the main field after four to six weeks to help reduce the transplanting shock and allow faster establishment,” explains Odhiambo, adding this is done when the sun is not hot, in particular early morning or late afternoon.

The seedlings are then drenched with insecticides to prevent early attack by aphids, thrips and cut worms.

Watering should be done early or mid-morning and not in the evening as this encourages phythium activities that cause dumping off.


Compost manure mixed with a compound fertiliser and with adequate phosphorous is used in every hole to hasten plant growth and help in fast root formation and reducing possible repetitive gapping.

“Chilli plant grows in different soil varieties, but for maximum production, they should be planted in deep fertile soils to allow proper root penetration as the plant is a heavy nutrient extractor that calls for periodic replenishment in line with the soil requirements,” Wangari says, adding that soil nutrients levels should always be checked to help determine the deficit element.

Chilli takes between 75-80 days to mature and harvesting continues for six months with good care.

Harvesting is done after every seven days and high levels of hygiene must be observed. One should have short nails not to injure the produce and each person is assigned a block or a portion where details of each are captured, including the weight of the rejects and quantity of produce.

The produce is later cleaned, dried, graded and packed, then forwarded to Kephis for inspection before it is exported.

“We harvest 100kg of bullet chilli every week, with a 6kg carton fetching Sh420. From African bird’s eye chilli, we get 156kg per week with a 6kg pack going for Sh780,” says Odhiambo, adding they further get 1.4 tonnes of capsicum, with a kilo selling at Sh60.

“With plastic mulch technology, there is firmness in the soil on a particular bed and nutrients are relayed to where they are needed. Less water is used as irrigation is targeted to the spot where it is needed. Evaporation is minimal with a high retention rate as mulch preserves much water. Less labour is employed and there is no spread of diseases during the rainy season,” says Okisegere Ojepat, the chief agronomist Tamlega Farm Care Limited, noting high initial cost is a hindrance to acquisition of the technology.


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Using pesticides on bullet chillies

  • If there is any spraying to be done, the recommended spray should not interfere with the harvesting.
  • The chemicals recommended should have a lower Post-Harvest Interval (PHI) such that the produce will be free from chemicals and safe for human consumption once the plants have been sprayed.
  • When the PHI period elapses the PH level should be checked and if okay, a white flag is raised to act as a green light to the farmer that the produce is safe and can now be harvested.