Rhizomes are harvested at different times, depending on their intended use. Fresh ginger might be harvested about 5 months after planting. For preserved ginger, they are usually dug up 5 to 7 months after planting, before they are fully mature but while they are still tender and mild.
For dried ginger, mature rhizomes with a full aroma, flavor, and pungency are harvested 8 to 9 months after planting. The essential oil content within rhizomes increases with age, so plants used for this might be harvested even later. They are harvested either by hand or by mechanical diggers and are graded according to local preference or end-use. They are sold fresh, dried or ground, or are processed into oil and oleoresin.
For fresh Ginger, the crop should be harvested before attaining full maturity means when rhizomes are still tender, low in pungency and fiber content, usually from fifth month onwards after planting. Harvesting for the preserved ginger should be done after 5-7 months of planting while harvest for dried spices and oil is best at full maturity. i.e between 8-9 months after planting when leaves start yellowing. Rhizomes to be used for planting material should be harvested until the leaves become completely dry. After digging the rhizomes should be treated with a fungicide like mancozeb @3-4 gm per liter of water, dried in shade, and stored in pits covered with a 20 cm layer of sand alternating every 30 cm layer of rhizomes. These pits should be dug under a thatched roof to protect the rhizomes from rain, water, and direct sun. The average yield varies from 12-15 tons per hectare. However recovery of dry ginger varies from 20-22%.
Washing and drying
After harvest, the fibrous roots attached to the rhizome should be trimmed off and soil is removed by washing. Rhizomes should be soaked in water overnight and then cleaned. The skin can be removed by scrapping with the correct instrument. Peeling or scraping reduces, drying time, thus minimizes mold growth and fermentation. However scraping process tends to remove some of the oils constituents which are more concentrated in the peel.
By removing the outside Corky skin the fiber content also decreases. After scrapping, the rhizomes should be sun dried for a week with frequent turning and well rubbed by hand to remove the outer skin. This is called as the unbleached ginger.
The peeled rhizomes should be repeatedly immersed in 2% lime solution for 6 hours and allowed to dry in the sun for 10 days while rhizome receive a uniform coating of lime and moisture content should be 8-10%. This is called as bleached ginger which has improved appearance with light bright colour.