The psychedelic artists Alex and Allyson Grey regularly welcome worshippers to their Chapel of Sacred Mirrors (Cosm) in Wappingers Falls, New York for full moons and “Art Church”. But Cosm only unveils a new lineup of contemporary Visionary art in their Entheon museum’s All One gallery once a year. They are opening their new exhibition Inner Sanctums, featuring works by 14 artists from Judy Chicago and Bo Bartlett to the South African sculptor Daniel Popper, on Saturday (15 March)—between the blood moon lunar eclipse on Friday and the vernal equinox on 20 March. It is only the gallery’s second exhibition ever.

“The vernal equinox is an auspicious time of year, celebrated by cultures worldwide as a time of renewal,” Alex and Allyson Grey explain over email.

The Greys first took LSD together at a party while Allyson was attending Tufts University in 1975, bonding them for life. They then moved from Boston to New York and became staples of the city’s downtown art scene over the following decades, showing at the Stux Gallery in Soho and attending the Church of the Little Green Man on the Lower East Side. In 1999, Alex met Adam Jones, the guitarist for Tool, and later made the album art for the band’s records Lateralus (2001) and 10,000 Days (2006).

The Greys formed Cosm as a non-profit in 1996 and hosted its inaugural full moon ceremony at the their Brooklyn home in January 2003. The fledgling “sanctuary for spiritual renewal through contemplation of transformative art”, as the Greys put it, decamped for Chelsea the following year. “It seemed, at the beginning, along the lines of the standard art gallery format,” says Jacaeber Kastor, a New York-based psychedelic artist, gallerist and historian, who has contributed two meticulous drawings to Inner Sanctums. By 2008, the Greys had raised $1.8m to buy a former Christian retreat sited on 40 acres in Wappingers Falls, and they established Cosm as an interfaith church.

“It was really a big space, but ramshackle and abandoned,” Kastor says. “It’s utterly mind-blowing what they’ve done.” Fifteen years and another $3m later, Entheon opened. The three-floor, 12,000 sq. ft former carriage house has a great hall and galleries focused on the Greys’ work, including the installation of Allyson’s drawings and painting Chaos, Order, Secret Writing, the 21 works in Alex’s Chapel of Sacred Mirrors series (which debuted at the New Museum in 1986), plus a “Psychedelic Reliquary” that includes the ashes of the psychologist and psychedelics advocate Timothy Leary.

Inner Sanctums will greet guests on Entheon’s ground floor with works in which artists reflect on their core creative psyches. The show features an intergenerational mix of artists challenging Visionary art’s subjective bounds.

“As our psychological space becomes occupied by distressing news feeds, it is ever more important to reclaim our personal power, to know and celebrate the sovereignty of our free and inspired imagination,” the Greys write of the show’s theme. “Every time an artist opens the eye of their soul, a new portal to Heaven or Hell can open.”

Three featured works from Judy Chicago’s Birth Project series (1980-85) envision the creation of a work of art as akin to the gestation of new life in a womb. Karla Knight’s buzzy extraterrestrial abstractions are also featured alongside works by historic Visionary artists like the poster designers Rick Griffin and Lee Conklin, the plein air painter Joseph Parker and Kastor, who explores sensations like the birth of matter while experimenting with form. Rising Visionary artists like the painters Naoto Hattori and Autumn Skye will round out the ensemble.

The works in Inner Sanctums are on loan from the artists, their galleries or the private collectors who own them, and only some are for sale. Aside from two works by the late Visionary artist Paul Laffoley that they purchased decades ago, the Greys have not bought much art. Instead, they have poured their funds into Cosm, which they see as a living, breathing “social sculpture”. They are still raising funds to wrap the Entheon building in an ornate bas-relief composition featuring dozens of 21ft-tall concrete faces, gilded eyes, winged beings and more.

Several artists from Inner Sanctums will convene for a ticketed panel ahead of Cosm’s vernal equinox party. Art Church will kickstart the Celestial Celebration, followed by a party featuring live music, art making, divination and more. The one element conspicuously not on the premises? Actual entheogens, the Greys repeatedly emphasise; the art and charged skies should provide plenty of psychoactive energy.

• Inner Sanctums, opening 15 March, All One Gallery, Chapel of Sacred Mirrors, Wappinger Falls, New York