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A 2022 Onion Farming Guide


Are you looking for advice on how to make your onion farming business thrive? Do you need advice on the best onion variety to plant in your area? Or do you need soil testing services to know if your land is free of pathogens? If the answer to these questions is yes, do not hesitate to give us a call for a free consultative session.

Onion farming in Kenya

Onion farming in the country is mainly done in Naivasha, Kajiado, Meru, and Oloitoktok. The crop thrives well in these regions because of the hot and dry climatic conditions. Onions are in high demand, with the prices fetching up to 100 shillings a kilogram. However, you must understand that this is a retail price. Wholesale prices {farm gate prices} are usually 30 – 40 shillings a kg.

In some circumstances, the farm gate price can fall up to 20 shillings a kg. Therefore, before you plant onions, you need to time the market. An excellent way to do this is to walk to the nearest market in your town and inquire when the prices are high. Yes, there is no magic way of timing the market. You need to do your research!

Though onions are hardy, farmers need to ensure that they do a soil test to determine whether their soil is contaminated or not. Also, soil testing services help farmers know whether there are enough nutrients to support a viable onion farming venture or not. Other benefits of soil testing services are

  • The farmer saves money because they only buy the required nutrient
  • The farmer avoids over-fertilization
  • You will know whether there are pathogens that can destroy your onions

How to Prepare Land for Onion Farming

Before preparing your land for onion farming, choose a suitable location. Onions thrive well in altitudes of 500 – 2000M above sea level. In addition, farmers should plant onions in regions with a rainfall of 500 – 700mm. If the rain is in excess, the bulbs will start to rot, increasing costs.

The soil should have good water-holding capabilities and have a PH of 6 – 7.

Land Preparation

Before planting onions, the farmer should ensure that the land had been ploughed at least three weeks earlier. The ground should also be harrowed at least three times to ensure the soil has a fine tilth. Before planting any onion seed variety, you must ensure the soil is well nourished by applying at least 40 tonnes of organic manure.

If normal organic manure {Cow dung} is not readily available, farmers can use an organic fertilizer  such as Safi Sarvi. Safi Sarvi is suitable for use on lands that have been acidified because of the use of chemical fertilizers. This carbon-negative fertilizer is created to increase yields by 30% and incomes by up to 50%.

Onion Propagation and Planting

For best results, you need to identify a suitable seed variety. Once you identify the seed variety, you must test it to know the germination rate. One way to test the germination rate is to take a few seeds and put them in a condition that will encourage growth. For example, you can soak cotton in water and wrap the seeds with the soaked cotton. 

After a few days, you should be able to see the seeds germinate. If the germination rate is more than 70%, the seed is suitable for planting. If the rate is below 70%, do not plant them.

Propagating onions in the nursery

The farmer should solarize the soil for nursery management to reduce soil-borne diseases. Solarization should be done when the heat is at its fullest to ensure soil-born diseases die. The nursery site should be close to a water source and have a gentle slope. The slope is important because it prevents waterlogging and encourages air circulation.

The nursery site should be free of debris, such as stones and weeds. If planting on a one-hectare piece of land, plant the seedlings on an area measuring at least 0.05 hectares. If you irrigate the nursery, ensure that a furrow is made on all sides of the land.

In addition, avoid flat beds because the seeds can be washed away. Instead, ensure the bed is raised. Also, it is essential to treat your seeds before planting them. When sowing the onion seeds, line sowing is advised.

Certain things must be done to ensure that the seedlings do not die. First, the farmer must ensure the seedling bed is free of weeds. Organic herbicides are advised in this case. The second thing is to ensure that the nursery bed is free of excess rainwater. Lastly, onion seedlings should be protected from direct sunlight by mulching.

Best Fertilizer for Onion Farming

The best fertilizer for onions is that which meets its nutritional requirements. For example, onions will require plenty of nitrogen to boost growth and increase the size of the bulbs. As an onion farmer, you need to be wary of applying too much nitrogen to the soil because it can promote foliar growth at the expense of onion bulbs.

If a soil test shows high nitrogen levels, potassium should be added to the soil. Potassium is essential because it increases the shelf life of onions. Farmers should only add sulfur fertilizer if the soil has low amounts. Sulfur is vital because it helps increase nitrogen uptake, which improves yields. 

Another important onion fertilizer is magnesium. Magnesium is important because it helps in chlorophyll production, which boosts nutrient uptake. Similarly, magnesium helps improve the shelf life of onions, meaning they can be stored for long periods without spoiling.

Most farmers do not know this, but boron fertilizer is also very crucial to the success of onions. Boron fertilizer is necessary because it improves onions’ storage quality and carbohydrate metabolism. Lastly, boron improves the movement of calcium inside the onion plant. 

Calcium is important because it increases the plant height and protects the bulb from abiotic stress such as salinity. Calcium is also applied to disease-infected soils because it improves the immunity of crops. 

The best fertilizer for onions should be organic fertilizer. Organic fertilizer has several advantages, such as being environmentally friendly and having the ability to improve the soil structure. Organic fertilizer has also been scientifically proven to increase yields by up to 30% and outcomes by up to 50%.

Onion Varieties

The success of an onion farming business will depend on the type of seeds you plant. The onion variety you choose should be able to adapt to your local climate and farming needs. For example, not all onion varieties are suitable for export use. Also, some onion varieties are too small to be sold in the local market. These are just some of the factors that every farmer should consider. Some of the onion varieties to consider are:

Red Creole Onion

The red creole onion variety is suitable for planting in hot climate areas because it requires minimal rainfall to thrive. This onion variety has a long shelf life, making it ideal for growing by traders. Consumers love this variety because of its pungent taste. Farmers can plant this onion on soils with pink rot diseases because it is pink rot resistant.

Red Creole produces small and medium bulbs with a yield potential of 15 – 28 tonnes an acre. Because of its high-yielding potential, this seed variety is suitable for commercial farming

Red Couch F1 

Red Couch F1 is a hybrid onion variety that is pink rot resistant. It has a maturity time frame of 80 -90 days and is identified from its flattened globe-shaped size. Unlike Red Creole which produces small and medium bulbs, this variety has medium and dark red bulbs. Red Couch F1 is preferred for use by the hotel and catering industry because of its large size.

To plant this variety, farmers should have a minimum capital of at least 100,000 -150,000 per acre to plant onions. It has a yield potential of 20 – 30 tonnes and can be stored for up to 90 days without spoiling.

To avoid spoiling, ensure that onions are put in a loose bag and are not placed on the ground. If placed on the floor, the humidity levels will increase, resulting in some of them rotting.

Texas Early Grano

Texas Early Grano has a white gold color with mild pungency. Hote prefers it because of its tasty flavor. This onion variety matures in 120 days and can do well in most ecological zones in the country. However, unlike the Red couch and Creole, this should not be planted in soils that have been infected with pink rot disease.

Red Pinoy

Red Pinoy onions can adapt to various ecological zones. It is suitable for export because it has a shelf life of six months. In addition, it has a yield potential of 25 – 30 tonnes and is resistant to diseases such as purple blotch and downy mildew. 

Red Passion F1 Onion

Red passion F1 is a hybrid red onion only suitable for planting in low and medium-altitude areas. It is resistant to several diseases such as the Purple blotch disease and the pink rot disease. It is important to note that purple blotch-infected soil can drop yields by up to 50%. This onion variety has good curing and storage capabilities. Red passion F1 takes 90 days to mature.

Onion Diseases to know about

To become a successful onion farming farmer, you need to know about the different diseases affecting your farm. The Purple Blotch disease can destroy up to 50% of farm produce. Some of the onions diseases to know about are:

Purple Blotch Disease

This disease is prevalent in almost all onion-growing regions in the country. Therefore, to be on the safe side, choose onion varieties that are Purple Blotch resistant. The main sign of Purple Blocth disease is small watery lesions attached to the leaves. These watery lesions turn brownish-purple as the lesions grow.

Purple Blotch mainly spreads when there is infected plant debris on the farm. It thrives better when leaves are left wet for more than 12 hours. When infected leaves dry out, the spores carrying the disease are spread from one plant to another each time it gets windy.

The best way to control these diseases is to ensure that there are no wet leaves on the farm. Also, avoid excessive irrigation and ensure adequate aeration between plants. 

Pink Root Disease

Infected plants look nutrient deficient, and the roots tend to have a light pink colour. Pink color is also seen on the skin of white onions. Pink root disease can stay in the soil as dormant spores or as a host on an infected plant. When not controlled on time, the disease can destroy the farm and cause retardation. 

Farmers can control the pink root disease by ensuring that they plant seed varieties that are pink root disease resistant. Also, farmers should implement crop rotation every four years.

Another common onion farming disease to know about is bacterial soft rot. This disease causes onion leaves to wilt and the scales to be soft and watery. When you squeeze infected bulbs, they will ooze fluid with a pungent smell. 

Get in Touch with an Onion Farming Agronomist

Onion farming is lucrative. However, a simple mistake, such as buying the wrong onion seeds, can cause heavy losses. To optimize the returns of your onion farming enterprise, we advice you to seek the services of a reputable and experienced agronomist. Do not hesitate to reach out to us if you require agronomy services. 


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