Soma is a great deity, cosmic power and spiritual principle in Vedic thought. It also had its counterpart in the plant kingdom. There has been a long search for the identity of the original Soma plant was and several plants have been proposed as representing it.
My view – based upon more than thirty years of study of the Vedas in the original Sanskrit, as well as related Ayurvedic literature – is that the Soma plant was not simply one plant, though there may have been one primary Soma plant in certain times and places, but several plants, sometimes a plant mixture and more generally refers to the sacred usage of plants. Soma is mentioned as existing in all plants (RV X.97.7) and many different types of Soma are indicated, some requiring elaborate preparations. Water itself, particularly that of the Himalayan rivers, is a kind of Soma (RV VII.49.4). In Vedic thought, for every form of Agni or Fire, there is also a form of Soma. In this regard, there are Somas throughout the universe. Agni and Soma are the Vedic equivalents of yin and yang in Chinese thought.
The Debate about the Soma Plant
Some modern scholars emphasize the plant ephedra (Ma huang in Chinese herbalism) as being the main Soma plant and connect it with Afghanistan and Iran, where ephedra is a common plant. They note that ephedra was the main Soma plant of the Persians. Ephedra commonly grows in different places in India even today, and is sometimes Somalata. So we can argue it has been one of the Soma like plants, but it does not appear to have been the only type, nor does it resemble the characteristics of the primary Soma plants described in the Rig Veda.
Soma is part of a vast watery and oceanic symbolism of Soma in the Rig Veda. The Rig Veda describes Soma as a watery plant, growing near water (RV VIII.91.1) and as flowing with a milky juice gained by crushing the plant. Ephedra, on the other hand, is a dry plant with very little juice.
Other scholars propose that the original Soma was the Amanita muscari mushroom, which is used by many shamans, particularly in Siberia. While I cannot say for certain that this mushroom was not a kind of Soma for some people, the Vedic Somas are described in very different ways. The Soma plant is described with leaves, which mushrooms do not have, and is often said to grow in water. Sharyanavat, the main Rig Vedic Soma land also refers to a lake and means ‘abounding with reeds’, with shara (Saccharum sara) being a type of reed related to sugarcane. Shara was mainly used to make arrows and was sacred to both Agni and Soma. Another later great Soma land of Munjavat also means ‘abounding with reeds’ with munja being a type of reed related to the same plant as Shara and considered to be the best of the Somas. This again shows Soma growing in marshy or aquatic areas and being some sort of reed. Some scholars have gone so far as to identify Soma with the sugar cane, another Saccharum species cultivated in ancient India. Sugar-cane was probably used in Soma preparations, if not another type of Soma. So the main Rig Vedic Somas were probably certain reed grasses, some of which do have nervine and nutritive properties.
The Atharva Veda (AV XI.6.15) specifically mentions five great plants of which Soma is the best, including marijuana, barley and darbha (kusha or durva), showing that many plants had Soma-like qualities. Here Soma is again connected with another type of reed (darbha, Saccharum cylindricum), which could have easily been pressed to get a juice, much like sugarcane. Soma is also connected with marijuana, suggesting that mind-altering plants were regarded as different types of Soma. Soma is in other places connected with kushta (Saussurea lappa), a kind of spicy nervine, and with the Ashvattha fig tree and said to grow in the Himalayas in the Atharva Veda (AV XIX.39.5, 6).
Other plants connected with Soma, which was often said to grow on mountain lakes, are the lotus and water lily. Like these Soma is described as having leaves that come out in a circular pattern like the Moon. Additional potential Soma like plants are members of the orchid and lily families. A number of these plants are nervines. Like Soma, they have milky juices, unusual leaves, and filaments. Their juice can be pressed out between rocks.
In general, Soma was prepared in three forms, as cooked with grain or barley (yava), milk (go) or curds (dadhi). While some Somas had their fresh juice used, it seems the majority were part of elaborate prepartions. Soma was often used with ghee (ghrita) and honey (madhu), which are sometimes synonyms for Soma. In fact, Soma was often called madhu (honey or mead). Special herbal honey preparations and herbal ghee preparations were additional types of Somas. As connected to honey and flowers, Soma is connected to lotuses and other flowering aquatic plants. Soma, however, was discriminated from Sura or wine and alcohol, though fermentation may have been used in preparing some types of Somas.
The great early Ayurvedic doctor, Sushrut, mentions 24 Soma plants, growing mainly on Himalayan lakes and named after Vedic meters. He mentions 18 additional Soma like plants, which are mainly nervine herbs. Soma, therefore, was likely part of an entire science of sacred plant preparations and not just one plant in particular. A number of Soma-producing and Somalike plants existed. The search for one single Soma plant is therefore misleading.
Soma was also connected to the practice of alchemy and as early as the Rig Veda, it was prepared with gold and possibly lapis lazuli, perhaps even with sea shells or pearls.
The Somas in India were mainly special powerful plants growing in mountain lakes and riverine regions. With the shifting of the rivers, this cult changed, but reverence for Himalayan plants and rivers remained a characteristic feature of the Hindu religion.
Soma and Yoga Practices
However, we must remember that the real Soma is a secretion in the brain from spiritual practices of Yoga, pranayama, mantra and meditation (an elixir prepared from the Tarpak Kapha or form of Kapha lubricating the nervous system in Ayurvedic though). Soma at a yogic level refers to the crown chakra, which is opened by Indra (yogic insight) and releases a flood of bliss throughout the body. This inner Soma is the main subject of the Vedic hymns, though outer Somas were also important. The Vedic Yoga centers on how to prepare
In conclusion, it may be wrong to look for a single Soma plant. Rather, Soma is part of the ancient, yogic and shamanic usage of sacred plants, including tonics, nervines and mind-altering plants of various types as well special preparations of them. Each group, community or geographical region probably had its own Somas or sacred plants. Soma is a transformative substance that can be found in many plants and has corresponding mind-altering substances that can be produced by the brain itself.
 AV XI.6.15. The five great plants, of which Soma is the best, appear to be Soma, darbha (a kind of grass), bhanga (marijuana), yava (barley) and sahas (identity unknown).