Agronomist notebook: Here’s how to survive the erratic rains

Friday September 13 2019
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Jessicah Emekwi checks tuta absoluta that she trapped on her tomato farm in Turkana County. In capsicum and tomatoes, the spread of early and late blight is high during the rainy season and the affected leaves should be pruned on bushy plants to reduce the spread of the diseases and allow the penetration of the chemicals while spraying. PHOTO | PETER WARUTUMO | NMG


Unpredictable weather conditions have affected farming in the country, with many farmers who rely on rains no longer knowing when and what to plant.

Pest and disease incidence has also increased, thanks to the cold and rainy weather in many parts.

For some maize farmers, whose crop is currently tasseling, the heavy rainfall currently being experienced in some parts of the country has come as a blessing. But for those harvesting beans and onions, the heavy rains have become a nightmare.

Jane, a bean farmer in Nakuru, is currently counting huge losses because the heavy rains have delayed the harvesting of the crop.

This has made post-harvest practices such as threshing and drying difficult because the beans cannot be threshed when wet.

The farmer has no choice but to uproot the beans because the rains will make them start germinating while still in the pods, resulting in losses.


Once uprooted, the beans should be sun-dried during the morning hours and stored preferably in a wooden store with proper ventilation to allow them to dry thoroughly.

For onion farmers, the medium-sized bulb is the most preferred by most consumers. However, the heavy rains normally result in more vegetative growth, leading to large bulb onions.

The rain is also affecting the curing of onions, making them sprout when harvesting. To avoid this, the farmer should neck the bulb onions for two days, uproot and store them in a dryer.

Necking is done by twisting the leaves where one cuts them off during harvesting. If the plant is still vegetative, you have to neck it to enable it dry so that you cut off the leaves later.


Failure to cut the leaves will make the bulbs sprout again and eventually rot. On the other hand, leaving them in the wet soil may lead to rotting of the bulbs, occasioning losses.

With the rain come dozens of diseases. Powdery mildew in crops like spinach is common due to the water splash. This should be controlled by ensuring timely harvesting of the spinach.

In capsicum and tomatoes, the spread of early and late blight is also very high during the rainy season. Prune affected leaves and bushy plants to reduce the spread of the diseases and allow the penetration of the chemicals while spraying.

Mulching the plants too helps in reducing the spread of fungal diseases since it controls splash erosion and prevents the fruits from touching the ground. Tomato greenhouse growers are experiencing a low rate of ripening due to low temperatures.

To curb this, the farmers should prune the leaves to expose the fruits to light, hence improving the rate of ripening.

To avoid leaching of nutrients especially after using nitrogenous fertiliser that are highly soluble in water, use a nitrogen stabiliser to ensure the plants utilise nutrients fully.

Also consider raising the beds before planting short crop varieties such as coriander that are likely to be submerged in case of flooding.

In areas where flooding is rampant, the farmer should consider constructing terraces and drainage channels to control soil erosion.

For long-term goals, grow trees and plants such as sweet potatoes that provide ground cover.

This is also the time every farmer must ensure that they harvest as much water as possible in water pans or tanks for irrigation.