I grew supermarket ginger for a few years. Sandy and fertile moist soil preferred, with quite a lot of fertiliser, and the more light and heat it gets the stronger the flavour. The leaves and stems are pleasantly scented too of course. Just place the rhizome 1-2 inches under the soil surface and wait a few weeks with it somewhere warm. Don't water it beyond keeping just moist until the shoots are a couple of inches above the soil (just to avoid rotting the unrooted rhizome). You need to start with a pot at least 10" diameter. It's a fast grower down there. I wouldn't plant in the open garden as the soil won't be evenly moist, fertile or warm enough for it to do more than a half-hearted attempt.
The first year you can expect shoots around 3 feet high, but too thin for using as stem ginger. I lifted it each autumn as the leaves died down and stored it dahlia-like over winter, planting again in spring. It needs a rather large tub after the first year, as the roots dont' grow well if constricted (you get thin wiry roots and few of the nice fat rhizomes), and the plant is not nearly as vigorous.
Easy enough to get a lot of fresh root for the kitchen, plus some thickish shoots for preserving the stems. I never saw flowers though.
I must try galangal, turmeric and cardamom some day. Anyone ever germinated seeds from culinary green or black cardamom pods?