What is real indigo – information and care for Tinctoria Indigo Indigofera tinctoria , often called real indigo or just indigo, is probably the best known and most widespread dye plant in the world. Cultivated for thousands of years, it has recently fallen somewhat out of favor due to the invention of synthetic dyes. However, it is still a wonderfully useful plant and well worth growing for the adventurous gardener and home dyer  . Read on to learn more about growing indigo plants in your garden.
What is real indigo?
Indigofera is a genus of over 750 species of plants, many of which have the common name “indigo.” However, it is Indigofera tinctoria that imparts indigo color, so named for the deep blue dye it produces that has been used for thousands of years.
The plant is thought to be native to Asia or North Africa, but it is difficult to be certain since it has been around since at least 4,000 BC. It was cultivated in the 4th century BC, long before good records of gardening were kept. It has since been naturalized throughout the world, including the American South, where it was a very popular crop in colonial times.
Today, Tinctoria Indigo is not cultivated nearly as extensively, having been overtaken by synthetic dyes. However , as with other indigo varieties , it is still an interesting addition to the home garden.
How to Grow Indigo Plants
Caring for indigo plants is relatively easy. Tinctoria Indigo is hardy in USDA zones 10 and 11, where it grows as an evergreen. It prefers fertile, well-drained soil, moderate moisture and full sun, except in very hot climates where it appreciates some afternoon shade.
The indigo plant is a medium-sized shrub and grows 24 to 36 inches tall and wide. In summer it produces attractive pink or purple flowers. It is actually the leaves of the plant that are used to make the blue dye  , although they are naturally green and must first go through a complicated extraction process.
Indigo Plant Harvesting – Tips for Picking Indigo for Dyeing
Many of us are familiar with the beautiful, faded blue hue made famous by the indigo plant  . For years, breeders used an indigo plant crop to create a dye  that is widely used around the world. It was the first dye to color Levi jeans. Although the natural dye’s popularity faltered when a synthetic dye was developed, the selection of indigo as a dye is making a comeback. If you want to learn how to harvest indigo to make your own dye, read on. We tell you how and when to pick indigo.
Choosing indigo for dyeing
Indigo plants have beautiful flowers, but it is the leaves and twigs that are used for dyeing. Although there are many types of indigo, it is true indigo ( Indigifera tinctoria ) that has traditionally been used for dyeing.
Note that neither the leaves nor the stems are blue. The blue dye comes out after the leaves are treated.
When to Choose Indigo
Before you start harvesting indigo, you need to figure out when to pick indigo plants. The ideal time of year to pick indigo for dyeing is just before the flowers open.
When picking indigo, remember that they are perennial plants  that must continue to photosynthesize to survive. For this purpose, never take more than half the leaves in a year. Leave the rest on the indigo plant so it can produce energy for the following season.
Once you have completed the indigo plant harvest, take immediate action. You should use the harvested indigo as soon as possible after you finish picking the plant for dyeing.
How to Harvest Indigo Plants
When harvesting indigo, you must first collect the leaves. Many people simply bundle leaves and small branches for processing.
After you’ve collected your indigo crop, you’ll need to treat the foliage to create the blue dye. Preferred techniques vary. Some who grow indigo for dyeing suggest that you start by soaking the leaves in water overnight. The next day, mix in building lime to achieve the pale blue color. Others suggest a composting method. A third way to extract the dye is water extraction.
Indigo Plant Varieties: Learn about different indigo plants
The popular color “indigo” is named after several plants in the genus Indigofera . These varieties of indigo are famous for the natural blue colors obtained from the plant leaves, which are used to make a natural dye  . Some indigo plant varieties are used medicinally, while others are beautiful and ornamental. Read on for more information about indigo plants and an overview of the different indigo plants.
Information about the indigo plant
According to Indigo plant information, these plants are native to both subtropical and tropical areas around the world. They are members of the pea family.
Some varieties of indigo plants have beautiful flowers. For example, the flowers of Indigofera amblyanthan are delicate pink clusters and are cultivated for their ornamental beauty. One of the most attractive indigo bushes is Indigofera heterantha , with its long clusters of pinkish-red, pea-like flowers.
However, it is the leaves that make most types of indigo famous. For many years, the leaves of certain indigo plants were used to make dyes to color fabrics a rich blue. It was once the most widely used natural dye in the world.
Production of dyes from indigo varieties
The blue dye is produced by fermenting the leaves with caustic soda or sodium hydrosulfite. Various indigo plants are used to produce the blue pigment. These include true indigo  , also French indigo ( Indigofera tinctoria ), natural indigo ( Indigofera arrecta ) and Guatemalan indigo ( Indigofera suffruticosa ).
These varieties of indigo were the center of an important industry in India. The cultivation of indigo for dyes slowed after synthetic indigo was developed. Today the dye is typically used by craftsmen.
While synthetic indigo produces a uniform blue, natural indigo contains impurities that produce beautiful color variations. The shades of blue you get from the dye depend on where the indigo was grown and the weather.
Medicinal Types of Indigo
Several varieties of indigo plants have been used medicinally, but true indigo is the most commonly used type and was popular among the Chinese to cleanse the liver, detoxify the blood, reduce inflammation, relieve pain, and reduce fever.
However , some indigo plants, such as creeping indigo ( Indigofera endecaphylla ), are poisonous. They poison grazing livestock. Other indigo plant varieties can cause diarrhea, vomiting, and even death when consumed by humans.
Watering Indigo Plants: Information About Indigo’s True Water Needs
Indigo  is one of the oldest cultivated plants, used for centuries and longer to produce a beautiful blue dye. Whether you are growing indigo in your garden to produce the color or just want to enjoy the pretty pink flowers and shrubs, indigo watering requirements are important to understand to help it thrive.
About the true water requirements of indigo
There are false indigo plants  , but true indigo is Indigofera tinctoria . It grows best and as a perennial in zones 9 and above; in colder areas you can grow them as an annual. Indigo is a small or medium-sized shrub that grows to about 1.5 m tall. You can prune it into a pretty flowering shrub that produces pink-purple flowers. The dye comes from the leaves.
Watering indigo plants is important to consider, not only for the shrub to grow and thrive, but also for dye production. Make sure your plant gets enough water and at the right frequency to keep it healthy, but pay special attention to water when harvesting leaves for coloring.
How to Water Indigo Plants
Unless you’re harvesting leaves to make dye, the water needs for indigo are pretty simple. If you have a well-established plant, it will be quite stubborn in the face of drought. Start by watering every few days of the growing season to help your shrub become established. The ideal conditions for the soil are evenly moist, so don’t let it dry out too much. Make sure the soil drains well. In winter you can water less.
Watering indigo plants becomes more important when making dyes. Studies have shown that the frequency of watering can affect how much dye you get from an indigo plant. For example, dye yields were higher when indigo bushes were watered every week than when watered every two weeks. It was also found that yield was higher when watering was stopped a week before leaves were harvested, compared to ten days or more.
If you’re growing indigo to enjoy a pretty shrub, water it regularly during the growing season until it’s established, and then only when there hasn’t been much rain. To harvest dye, you should continue to water your indigo at least once a week, even after it is established.