News and knowhow for farmers

Urine-wood ash mix is farmer’s cost-free pesticide

Small-holder farmers in Kenya can tremendously slice production costs by using urine and wood ash mixture to deal with crop pests and diseases.


This method has worked for thousands of Ugandan farmers who are saving more than 40 per cent of losses to pest and diseases.


The farmers in Masindi, Kapchorwa, Mukono, Buike and Nwoya districts are producing chemical-free fruits, vegetables, tubers, nuts grains, among other crops.

The commonest crops include bananas, oranges, cotton, maize, tomatoes, groundnuts, watermelon, cabbages, simsim, onions and potatoes.


Urine and wood ash are easily available in the farm. Urine can be obtained from humans and animals while wood ash can is collected from cooking places.




A mixture of the two kills small soft-skinned pests like aphids, maize stalk borers, banana weevils, mealy bags on jack fruits, among others.


The concoction also controls coffee leaf rust and groundnuts blight.


In addition, it enriches soil nutrients by adding nitrogen from urine and potassium and sodium from the wood ash.




The farmers use different preparation procedures to meet needs of different crops and diseases.


According to the Food and Agricultural Organisation’s Teca segment, dilution of urine is core in reducing ion concentration, which can burn the crops.


Urine must also be tightly sealed after harvesting to prevent escape of ammonia-the nitrogen component- and contamination from external microbes.


Dilution involves adding clean water, with a half a litre of water against two litres of urine beig the most common.


But other farmers use one litre of water against a similar amount of urine.


Although Teca does not give specific measurements of ash, the firewood by products is more or less harmless to the soils and indeed crops.


Before application, it can be filtred to remove big residues, which can block the nozzle of the pump.


The potassium and sodium in the ash helps in reducing soil acidity because they form alkaline ions. This boosts crop growth because the ions help in movement of nutrients in plants.

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Urine is kept in the shade for three days before use.


For aphids in passion fruits and blight in groundnuts, the farmers add half a litre of clean water to two litres of urine and some ash. The mixture is kept in the shade for another three days ahead spraying.  


It is applied immediately after the appearance of the pests and a repeats is done in two weeks.


The same procedure is followed in controlling maize stalk borers but application is done between the fourth and sixth weeks after planting.


Subsequent applications are done on seven to 14 days intervals.


It has is being used in Masindi District.


Kapchorwa District cotton farmers store urine for two weeks before adding half a litre to two litres of water and ash.


The mixture is left for another two weeks before application.


Aphids on oranges and jackfruits can be eliminated by adding 20 table spoonfuls to one litre of urine before spraying.




Animals like goats and cows will not feed on these crops because of the urine smell.


FAO says the preventive mechanism has to be done with care to avoid increasing soil salt, which will affect growth in the future.


Similarly, urine from unknown sources could increase risks of spread of diseases, therefore, it should be avoided.


FAO’s Teca segment informs small-holder farmers on new technologies of increasing productivity.

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