Evaluation of a Low-Cost Onion Powder Process for Smallholder Farmers in Southern Africa
8.67 - Evaluation of a Low-Cost Onion Powder Process for Smallholder Farmers in Southern Africa
Ashna Maharaja, University of Guelph, Canada
Suggested citation for this chapter.
Maharaja, A. (2026) Evaluation of a Low-Cost Onion Powder Process for Smallholder Farmers in Southern Africa. In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. farmpedia.org
Background to Onion Powder Processing
Small-scale farmers in Africa often lack adequate post-harvest storage facilities for their agricultural produce. For example, in Nigeria, it is estimated that 50% of the onion harvest is lost due to insufficient storage infrastructure (Sasakawa Africa Association, n.d.). Furthermore, regions such as Southern Africa experience prolonged dry seasons, during which vegetable cultivation becomes challenging without adequate irrigation. The United Nations Food and Agriculture Organization (FAO) reports that over 40% of Africa's population depends on agriculture for their livelihood, yet only 4% of farmland is irrigated. Irrigation remains essential in countries like Mozambique, where onions require specific water conditions to thrive (Sasakawa Africa Association, n.d.). With their shallow root systems, onions need frequent watering; soil moisture should not fall below 50%, and plants should receive approximately 1 inch (2.5 cm) of water per week (Government of Manitoba, n.d.). As onions are integral to many cultural cuisines, their availability remains important even during dry periods. This situation presents both a problem and a potential business opportunity.
Women benefit from the profits from their vegetables in home gardens which can help lift families out of poverty. Therefore, the absence of these profits in dry periods negatively impacts the financial status of families (Hope, 2025). Fortunately, small scale farmers have found a solution to counteract the wasted onions that occur due to a lack of storage facilities and the fact that they cannot be grown in the dry periods in non-irrigated areas. This solution involves the processing of excess onions into onion powder (Li An Machinery, 2024). Additionally, this post-harvest innovation provides more income to women due to the value-added nature of onion powder.
How small-scale farmers can make onion powder
The onions that cannot fit in storage facilities are used by farmers to make onion powder (Li An Machinery, 2024). Additionally, onions can be different shapes and sizes when harvested, and consumers tend to purchase the best-looking ones and leave behind the unsellable or "ugly" onions. These "ugly" onions and the ones that cannot fit in storage facilities are used in the onion powder making process (Li An Machinery, 2024).
Equipment required
Figure 1. Mortar and pestle (Lopez, n.d.)
Figure 2. Knife (Food & Wine, 2023)
Step by step process (Source: Sundried Onion Powder @SimpleHomeFood How to Make Onion Powder, n.d.)
1. Sort the onions
Utilize the onion surplus that cannot be held in storage units and that are "ugly". Onions that are "ugly" just mean that they are unfit for the market because they lack desirable qualities, such as a round size and being free from blemishes.
2. Wash and peel
Remove both the dirt and dry skins (brown peels) of the onions to avoid contamination of the powder.
3. Slice onions into thin slices
Use a knife to cut the onions into thin, uniform slices.
Figure 3. Cutting onions into thin slices using a knife (Source: Sundried Onion Powder @SimpleHomeFood How to Make Onion Powder, n.d.)
4. Sun dry the onions
Separate and spread onion slices on a flat surface (a piece of wood or a cloth) and set them in the sun to dry out. Fresh onions are usually harvested at about 86% moisture and need to be dried to roughly 7-10% moisture for stable storage. Depending on the weather, this step could take around 20 hours of open sunshine.
Figure 4. Spreading onions on a flat surface in the sun to sun dry (Source: Sundried Onion Powder @SimpleHomeFood How to Make Onion Powder, n.d.)
5. Check the dryness
The onions should be flaky and crispy to the touch.
Figure 5. Sundried Onion Flakes (Source: Sundried Onion Powder @SimpleHomeFood How to Make Onion Powder, n.d.)
6. Grind into a powder
Place the sun-dried onions in a mortar and use a pestle to grind into a powder.
Figure 6. Using a mortar and pestle to grind spices (Grommet, 2017).
7. Package it into bags
Package onion powder into clear sealable bags.
Figure 7. Packaging for onion powder (Source: Alibaba.com: Link)
Benefits to Smallholder Farmers
Onion powder processing allows smallholder farmers to convert otherwise wasted vegetables into a profitable venture. Rather than these onions go to waste or be sold at a cheaper cost, converting them to onion powder will add value to the product. This means that smallholder farmers can sell onion powder at a significantly higher price than whole onions. This brings more income to the family in a low-cost way with traditional methods and minimal equipment. Knives, a mortar and a pestle are staples in African households because they are needed to make traditional dishes (Kennedy Bobie Entertainment, 2023). This equipment, along with sunlight, is free to farmers, and the packaging, which is often locally available, is inexpensive.
To reiterate, due to the long seasonal drought in Southern Africa, smallholder farmers are burdened with irrigation issues (WMO, 2024). Farming is the livelihood of many women in Africa, including onion cultivation in home gardens, meaning that droughts negatively impact them financially (Hope, 2025). The introduction of onion powder processing acts as a value-added product to help compensate for these challenges, helping provide them with cash income in the dry season, when many families are forced to migrate to cities for low-wage jobs (WMO, 2024). Additionally, doors can be opened to more business ideas, and entrepreneurship, such as selling cooked foods at markets, which can bring even more income to women and their families.
Aside from the financial benefit, smallholder farmers also benefit from a convenient alternative for cooking with a longer shelf life than whole onions, making this critical additive accessible in the dry season. Onion powder also adds vitamins and minerals to the family's diet during this critical period when significant malnutrition occurs (Rdn, 2025). Onions contain many antioxidants and sulfur-containing compounds, which help reduce the risk of cancer, lower blood sugar levels and improve bone health (Rdn, 2025).
A similar process could be adopted for other vegetables, such as garlic and chili peppers. A combination of different vegetables could provide farmers with another product that they can add to the market and sell at an even higher price.
Critical Analysis
Although onion powder processing provides a low-cost method for smallholder farmers to reduce food waste and create value-added products, there are several limitations that must be considered. One major challenge is the labour intensity of the process. The steps involved, including slicing onions, transporting drying trays, sun drying, and grinding with a mortar and pestle, require significant physical effort. Since women comprise 50% of sub-Saharan Africa's 33 million smallholder farmers, similar to other regions of the world (Hope, 2025), this additional work may add to their already demanding responsibilities related to farming, childcare, and household duties. The process can be reduced by access to a more technologically advanced method (oven and blender/food processor), for example purchased by women’s cooperatives.
Another limitation is the dependence on weather conditions during the sun-drying stage. Proper drying requires consistent sunlight to reduce onion moisture to safe storage levels. However, humidity, rain, dust, or insects can affect drying conditions and potentially reduce product quality or lead to contamination if the onions are not fully dried. Maintaining good hygiene during preparation and grinding can also be difficult in open environments, which may affect food safety.
Market access may also limit the profitability of onion powder production. Although converting onions into powder increases their value, smallholder farmers may face challenges related to packaging, transportation, and reaching larger markets. In some cases, alternative technologies such as solar dryers, food dehydrators, or mechanical grinders could improve efficiency and product quality. However, these technologies may require investments that are not always affordable for smallholder farmers, but perhaps enabled by women’s farmer groups.
Despite these challenges, onion powder processing remains a practical solution for reducing post-harvest losses and increasing income opportunities and micronutrient nutrition for smallholder farmers during the critical dry season, as long as appropriate drying practices, hygiene, and market access are considered.
Helpful links to get started
Link - (A video showing the process of sun drying onions.)
Link - (A video showing an advanced process of making onion powder.)
Link - (A video tutorial on how to use a mortar and pestle.)
Link - (A video showing the traditional use of a mortar and pestle.)
Link - (A video showing how to make a spice blend using a mortar and pestle.)
Link - (A tutorial on garlic powder processing using a mortar and pestle.)
References
Bjarnadottir, A. (2025, December 5). Onions 101: Nutrition facts and health effects. Healthline. Link
Food & Wine. (2023, November 14). The 6 best knives for cutting vegetables, according to our tests. Link
Government of Manitoba. (n.d.). Onion cultivars. Manitoba Agriculture’s Vegetable Specialist. Link
Grommet. (2017, September 27). Spices from scratch. Here’s how [Video]. YouTube. Link
Hope, L. (2025, August 12). 33 million women grow food on plots in sub-Saharan Africa. Greener farming can boost their earnings – study. The Conversation. Link
Kennedy Bobie Entertainment. (2023, June 30). Mortar and pestle African culture and nature episode 1 [Video]. YouTube. Link
Li An Machinery. (2024, December 10). Innovative onion processing: Transforming onions into value-added products. Li An Machinery Food Processing Specialist. Link
Lopez, A. (n.d.). Women’s hands hold pestle pounding leaves in a big wooden mortar [Photograph]. Dreamstime. Link
Sasakawa Africa Association. (n.d.). New technology helps farmers improve onion shelf life. Link
Simple Home Food. (n.d.). Sundried onion powder [Video]. YouTube. Link
Tandane, H. J., Francisco, B. F., Maholele, A. J., & Sitoe, M. M. (2025). Irrigation challenges, water access, and adaptation strategies in smallholder farming: Evidence from Gaza Province, Mozambique. Global Challenges, 10(1), e00342. Link
WMO. (2024, September 2). Africa faces disproportionate burden from climate change and adaptation costs. World Meteorological Organization. Link