GINGER PRODUCTION

GINGER (Zingiber officinale)

Other names: Official ginger, Tangawizi 

Ginger is native to India and China. It was one of the earliest spices known in Western Europe, used since the ninth century. The rhizomes contains gingerol, an oleo resin that accounts for the characteristic aroma and therapeutic properties.

Utilization

• Ginger is sold as whole raw rhizomes, dried and powdered ginger, preserved or ‘stem’ ginger also crystallized and pickled ginger.
• Fresh ginger is used in pickles, chutneys and curry pastes. Dried and ground ginger is a constituent of many curry powders.
• Rhizomes produce green sprouts which can be finely chopped added to a green salad. 
• Dried ginger is used in cakes, biscuits, bread, puddings and jams and in some drinks like ginger beer, ginger wine and tea.

Cultivars grown in Kenya

It is essential to get the right cultivars of ginger to meet specific market requirements. Cultivars vary widely in quality and chemical characteristics. There are 3 known types of cultivars: Jamaican with an off-white color regarded as best quality, the Kenyan and Indian cultivars, both with dark skin and regarded as inferior.

Ecological requirements

Ginger is tolerant to a wide range of climatic conditions. It requires a tropical climate with heavy rain period followed by a hot dry spell. In Kenya ginger is grown on a limited scale in the Coastal Lowlands. However opportunities exist to grow the crop in Western Kenya, mainly in counties bordering the Lake Victoria.

Altitude

The crop can grow in areas ranging from coastal lowlands to 1500m above sea level.

Rainfall

Ginger requires 1000-2000mm of rainfall annually

Temperature

The optimum temperatures range for growing ginger is 25-30⁰C with a mean annual range of 18-27⁰C. Ginger is not frost tolerant and low temperatures induce dormancy. Temperatures above 32⁰C and intense sunlight can result in leaf scorch particularly in young plants. To minimize the leaf scotch due to high temperatures it is recommended that the crop is interplanted with a cover crop to provide shade, but ginger is best grown under open cultivation

Soils

Ginger requires fertile well drained loamy soils. Heavy clays restrict the development of bold smooth rhizomes. On heavy soils, attention should be given to providing good drainage. Ginger thrives well in slightly acidic soils with pH range of 4.5-6.5

Land preparation

Land preparation should be done early at least 2 months before planting. Deep cultivation is required to ensure adequate rooting depth and to eliminate perennial weeds. It is important to incorporate well decomposed manure to adjust soil pH and organic matter levels by the time of planting. Ridging is necessary for best performance.

Propagation

• Rhizomes for propagation should be selected at harvest, hardened and stored until next season.
• The rhizome fingers are separated into setts each approximately 2.5cm long and with at least a visible eye to give rise to a new plant.
• Setts should be pre-germinated before planting by covering with moist organic a layer of damp sawdust.

Planting

• Before planting, the setts should be dipped in a fungicide solution to minimize fungal infection, followed by hot water treatment for 20 minutes at 48⁰ C to eliminate nematodes.
• Setts are planted on ridges 25-30 cm apart, 15-30cm within rows and at a depth of 5-10 cm. Adequate watering is necessary for uniform germination. Shoots start appearing after 10-15 days and will continue over a period of 4-8 weeks.

Seed rate

The recommended seed rate varies from 1.5-1.7 tons/ha, depending on when the crop is to be harvested, higher rates used if the crop is to be harvested early.

Fertilizer requirement and application

Recommended fertilizer rates vary from 100-200kgN/ha, 65kg P/ha and 80-165kg K/ha. Phosphate fertilizers should be applied and incorporated into soil prior to planting, N and K should be applied in 2 splits- 1^st at 1-2 months after planting, 2^nd at 3-4 months applied in bunds along ridges. N can be applied in irrigation water.

Manure requirement and application

Ginger responds to organic manure and recommended rates vary from 20-50 tons/ha farmyard manure or compost to be applied before planting.

Weeding

Weeding is critical due to an extended germination time, slow initial growth and poor early ground cover. Manual weed control should be done with minimal disturbance to avoid crop damage. Perennial grasses must be eliminated before planting.

Pest

The most common pests of ginger are the nematodes, Meloidogyne incognita and M. javanica. The nematodes cause damage to the rhizomes and recommended control include crop rotation after every 3-4 years.

Chilies are commonly rotated with ginger. Old banana fields are not suitable due to risk of nematodes infestation

Diseases

The major diseases of ginger are soil-borne fungal rots caused by Pythium spp, Fusarium spp and Sclertium spp which flourish in conditions of high moisture. Proper drainage and crop rotation reduces the buildup of soil borne pathogens.

Harvesting and post harvest handling

• Full maturity is attained at 8-10 months when leaves turn yellow and start to lodge. Harvesting is done when plants are fully matured but depending on the market, harvesting can be done before full maturity.
• As plant matures volatile oil content decreases and fiber contents increase. Ginger rhizomes for preservation are harvested at 7 months when fibre content and pungency is still low. Ginger for fresh and dried products is harvested when volatile oil content is at maximum, at 7-9 months.

Storage requirements

• For fresh ginger, the rhizomes are washed immediately after harvest and air dried in shade for 1-2 days to partially heal wounds prior to packaging and storage.
• Fully matured ginger rhizomes are harvested and sun-dried for longer preservation. The rhizomes are stored in slatted or wire sided boxes under cool conditions.
• The packaging should be designed to allow moisture to evaporate.
• Rhizomes can be stored for up to 6 months as rhizomes are adaptable and easily stores in cupboards or in refrigerators. Dried and powdered ginger is stored airtight containers.

Yield

The average yields of 10 tons/ha fresh ginger are realized while yield range for dried ginger is in order of 15-25% of fresh weight harvested