Saffron colour is associated with Hinduism. Donning Saffron robes is the hall mark of a Sanyasi,one who has renounced everything in Life. Saffron color has now become a symbol of Hinduism.
On careful examination of Vedic texts and Smriti does not give a clue about Saffron being the colour of Hinduism, let alone Sadhus.
Hinduism is not an institutionalised one. Nor does it have any Prophet or Founder. Spiritually, in Hinduism is personal and it does not brook external symbols , excepting in instances where Tantra ,Yantra worship is practiced.
Renunciation is the embodiment of leaving everything, including the Sankalp for the Moksha or Self liberation.That is True Sanyasa.
As to Sanatana Dharma, as I have been writing in my articles, is an approach and a way of Living that is unique to one’s Nature,Swabhava. If one were to search for Temple worship in the Vedas, he would not find it. Nirguna Aradhana, that is Worship or meditating upon The Reality as a principle which is beyond Attributes is recommended.
As it is difficult to meditate upon ,for normal human beings, the concept of Worshipping individual Deities was introduced.This is Saguna Upasana,the worship of Reality in the form of a Specific God . The Saguna Aradhana is the first step towards Nirguna Aradhana.In this, there is no room for any symbols.
I have found some interpretations. I am reproducing them here.
All explanations seem to be convoluted ones, where the explanations seem to be of individual opinions. But none of them seem to have any authority sanctioned by either Sruthi (Vedas) nor Smritis.
Smritis do not prescribe any specific color for performance of Samskaras. It recommends dry white Dhoti for auspicious occasions and wet ones for Inauspicious ones. The dresses we ascribe to Gods and Goddesses including Navagraha are only the expressions of Saguna Upasana.
Any additional input with authentic texts welcome.
Two religious reasons:
1. Ancient Hindus worship fire. Well known reason.
2. Ancient Hindus worshiped Lajja Gauri, the Goddess of fertility. Fertility is naturally denoted by the color red. For reasons which will become obvious if you follow the Wikipedia link, I cannot include a picture of the Goddess.
One geographic reason:
Rubia cordifolia produces Alizarin which was used as a dye. The dye was used extensively with henna.Cultural reason:
Ascetics adopted the color to denote purity(since fertility and purity are intertwined). It came into extensive use since antiquity. The color was not as extensively used in the middle ages as many people would like to believe, it gained prominence with the Hindu Nationalist movement in the late 1800s. The rest, as they say is history.https://www.quora.com/Why-is-the-color-saffron-so-important-in-Hinduism-and-otherwise-to-Buddhists-and-the-Sikhs-as-well-I-have-noticed-that-even-Swami-Agnivesh-who-has-often-been-termed-as-anti-Hindu-by-extremists-chooses-to-always-wear-saffron
In Sanatan Dharma, the dark saffron colour indicates sacrifice, religious abstinence, the quest for light and salvation. Bhagwa is the most sacred colour for the Hindus and is often worn by sadhus who have left their home in search of the ultimate truth and serving the society before self.
It is to be said, in the earlier times Hindu saints were always fond of nature. One of the biggest components of Vedas is the “Aranyakas” – experiments with nature. Two of the most impressive things that Hindu saints found were – Sandhya (time of sunset/sunrise) and Agni (fire). A big part of Vedas is about extolling the virtues of the Sun and Fire. Thus these three predominant colours of sunset and Agni are yellow, orange/saffron and red became the holiest colours of Hinduism.
Hindu saints and spiritual stalwarts have always been saying things based on their experiences. As per legend, we experience saffron colour when we reach to Samadhi. When your energy flows from Muladhara (Root Chakra) to Sahasrara Chakra (Crown Chakra), and you awaken the entire Kundalini, the colour which you experience is Saffron.
We have seen Bhagwan Rama, Bhagwan Laxaman and Mata Seeta wore saffron during their exile and also saints they met during their journey. https://arungovil.in/importance-of-saffron-colour-bhagwa-kesari-in-hinduism.html#:~:text=In%20Sanatan%20Dharma%2C%20the%20dark,serving%20the%20society%20before%20self.https://arungovil.in/importance-of-saffron-colour-bhagwa-kesari-in-hinduism.html#:~:text=In%20Sanatan%20Dharma%2C%20the%20dark,serving%20the%20society%20before%20self.