Project Description

Stevia rebaudiana

Stevia is a small (60-75cm) green plant native to South America. Its leaves can be 30 times sweeter than sugar.

Environmentally speaking, 1 hectare of stevia is equivalent to 60-90 hectares of sugarcane in terms of sweetening power. So the use of stevia promotes the smart use of land and water.

Due to its natural origins, great taste and health benefits, stevia is used worldwide as a sugar substitute and/or complement in foods and beverages.

Stevia propagation trials with the Crop Science Department at the University of Zimbabwe are underway.

During the 2015-16 rainy season, BIZ and the Bulawayo Projects Centre will trial-grow and process stevia with small-scale farmers in irrigation schemes in Matabeleland South.

Where it does well: Wild plants occur on acid soils that are constantly moist, often near the edge of marshes or streams where the soil is sandy.

About 60 years ago, stevia was taken from its natural environment to be propagated in Japan. Today, it is cultivated in East Asia (China, Korea, Taiwan, Thailand and Malaysia) and can also be found in Brazil, Colombia, Peru, Paraguay, Uruguay, and Israel.

The plant is a tender perennial, meaning it survives mild winters.

It prefers a lightly textured (sandy loam or loam), well-drained soil to which organic matter has been added. As the plant cannot tolerate drought, frequent irrigation is required. In hot, sunny climates it will do best in semi-shade.

Planting – harvesting time – what is harvested: Stevia seed is known for its low germination rate even with optimal seed. A much simpler way is the vegetative propagation from cuttings. Tissue culture is also a solution for mass propagation of stevia.

The first harvesting can be done 4-5 months after planting. Subsequent harvesting can be done every 3 months, often at a time when producers have no other income. In temperate regions, stevia leaves are harvested once a year. The sweetener in the leaf is at maximum levels just before the plant flowers.

Harvested leaves need to be dried. The dried leaves are then powdered and sieved.

Average yield: The plant can yield around 6 tonnes of dried leaves per acre every year.

Stevia cultivation has traditionally been done by smallholders due to labour intensity. However, producers need to improve their competitiveness, especially increase productivity and product quality, as productivity is now up to 30% higher for mechanised and large-scale producers. Increased coordination of smallholders could also help them remain competitive vis-à-vis large-scale production.

  • Natural, calorie-free and low in carbohydrates
  • Stevia is the only sweetener with a glycemic index of 0, which means people who consume stevia can be assured that their blood sugar will stay stable.
  • It is stable at high temperature which makes it an excellent sweetener for cooking and baking.
  • Stevia possesses antimicrobial properties, and thus may actually help prevent tooth decay.
The fresh or dried leaves, green herbal powder, white powder extract, and clear liquid concentrate are used as a sweetener and sugar substitute. Stevia represents the best potential replacement for artificial sweeteners like saccharin and aspartame.
  • Stevia is recognised as a food additive or dietary supplement in a number of countries. It has been accepted for use as a food additive in the USA since 2008 and was approved for use in the EU in 2011.
  • The increase in number of diabetic and health-conscious individuals is pushing forward the need for natural, non-caloric alternatives to sugar.
  • According to WHO estimates, stevia has potential to replace 20-30% of all dietary sweeteners in the coming years. Expected revenue from stevia will be between USD 8-11 billion by 2015.