Turmeric the spice is the edible rhizome.
There are many types of curcuma longa, with the color ranging from a deep yellow to deep orange, and almost red.

White turmeric is actually called curcuma zedoaria.

TURMERIC

Curcuma longa

Turmeric hardly needs an introduction.
It is used both as a culinary spice and a medicinal herb.

Turmeric is a flowering, perennial, herbaceous plant that grows up to 3' tall.  It is a member of the ginger family Zingiberaceae.  Turmeric loves rich soil & partial sun.

Leaves emerge in the late spring when the weather stays over 60° at night:  typically about April 15 to May 1st in Gainesville.  Flowers sometimes occur first, sometimes after the leaves, but always early in the season.

Leaves will go horizontal and die off when the night time temperatures dip below 60° again. Once the tops die, rhizomes are ready to be harvested or divided and replanted.

CARDAMON

Elettaria cardamomum

True Cardamon is a tall growing ginger originally from southern India.  It can be anywhere from 6-13' tall in its native environment.   Ours stays about 3-4' tall in Alachua County area.   It has also naturalized in many other countries, including Costa Rica.

Cardamon is a shade loving, herbaceous perennial for zones 9-12.   It begins to flower at about 3 yrs old,  and continues to produce for 10-15 yrs.   But it only flowers in hot, humid conditions,  outdoors:  much like a rainforest.  
It seems to tolerate our cold winters in Gainesville most years without losing foliage.

It is the seeds inside the pod of the plant that are ground up as a spice. Cardamon has very pungent flavor and is often an ingredient in Curry flavoring.  A little goes a long ways.   Sometimes used to flavor coffee and tea, cardamon is quite aromatic.

(Asian) Common GINGER 

Zingibar officinale

Ginger is basically a tropical plant but thrives in our zone 8b-9 easily if rhyzomes are protected in the winter.  Tops will die off when nighttime temperatures drop below 60°.  They sprout green again usually by April 20 - May 1st in our area.   Grow outdoors in zones 9-11.

Traditional (Asian) ginger loves a partial shady environment with filtered sun or what we call bright sun. Rich well-drained soil with frequent watering when we're not experiencing heavy rainfall is ideal.  Rhyzomes will easily spread in clumps underground, shooting up new tops as it goes.  Flower is yellow.

Young rhyzomes harvested in early to mid-Fall will have the sweetest flavor.

Fun Fact:   Ginger was actually the first spice introduced and cultivated in the New World in 1585!

Costus can be easily propagated by rooting stem cuttings in the warm months of the year. Lay 8-10" stem pieces flat in the ground, lightly covered with dirt and keep moist.  In just three to four months you'll have new 12" tall plants.

Costus pictus can be grown simply as a beautiful ornamental.   Single flowers attract butterflies and birds when in bloom.

It is the leaves of this ginger, not the rhyzomes,  that are the subject of many studies regarding insulin regulation.

Spiral Ginger:   'Insulin plant'

Chamaecostus cuspidatus

aka Costus igneus  aka Costus pictus

Spiral ginger thrive in our hot, humid, tropical climate in north central Florida. Water frequently to maintain a rain forest like environment.  They do well in partial shade with bright, indirect sunlight. No full sun.

In late summer, Costus pictus begins to bloom.  A single flower emerges at the end of a stem,  looking more like a misplaced miniature orchid than a ginger. White interior with a yellow throat, red stripes adorn the top of the outer petals on this little jewel.

Chinese Ginger:
Thai Turmeric  /  Thai Ginseng  / Chinese Keys

Bosenbergia rotunda

Chinese Keys ginger is actually not native to China:  it's from Java and Sumatra.  Now can be found growing all over North America, most of Asia, and Australia.

Chinese Keys ginger has light green foliage  that grows to a height of just 2' tall.   It prefers semi-shade to medium sun.

Dainty lavender, orchid shaped flowers adorn the stems all summer long.

Chinese keys bears a number of finger shaped, long pencil-thin roots emerging from each fat bulbulous rhyzome, hence the English nick-name, Finger root.

Roots of Thai Turmeric are bright yellow inside, quite aromatic, and sweeter, less pungent, but spicier than traditional ginger.  

They are often used fresh as thin slices garnishing a salad, or added to soups and pickle recipes.

Sometimes called Thai Ginseng,  Finger-root,  or  even (erroneously) Lesser Galangal.

It can be propagated by division of the short, branching fat rhizomes.  Grows more slowly, and more delicately than traditional ginger.

Alpinia Officinarum:  Lesser Galangal

Alpinia officinarum

Alpinia Officinarum ginger has light green leaves that grow to approximately 3' tall, sometimes taller.  Prefers sun to partial sun.

This is similar in taste to Asian ginger but with a stronger, almost sharp, more peppery flavor.  Often served in slices atop a dish, simply for extra flavoring.  Used in Thai cooking more often than Greater Galangal.  Sometimes substituted for Asian Ginger in recipes.

Lesser Galangal ginger  originates from southern China and is cultivated in Indonesia, Malaysia and other parts of Southeast Asia including Vietnam and Hong Kong.

Siamese Ginger:  
Thai Spice Ginger / Greater Galangal

Alpinia galanga

Alpinia galanga,  aka Greater Galangal or Siamese ginger, grows 4-6' tall and prefers full sun to part shade. Suited to zones 8b-10.  White flowers are streaked with red.

Commonly called Thai Spice Ginger,  it is larger in size, with a more robust, pinkish-white rhizome and a sweeter, milder taste and odor compared to Lesser Galangal.  It has a very floral aroma with a citrus-y,  almost pine-like taste.

Alpinia galanga is native to India, Southeast Asia, and Laos,