purchase a ginger root from super mkt, or health food store
make sure it is nice and fresh with a shiny sheen
cut a 2" length,place tooth picks in each end place in a glass of water,when it has 1"/2" roots pot in a pot 3 times bigger than the piece,in a good rich potting soil do not let dry out,or to soggy,,place in indirect light.. it is a beautiful plant, and if lucky you will be rewarded with fragrant blooms.
you can also harvest fresh ginger from the roots~