This Sunday is the first day of spring, but it also marks an important spiritual and astronomical event: the vernal equinox. For many people, it's a day of celebration, since it symbolizes the rebirth of nature in the Northern Hemisphere. But like any holiday that's as old as the seasons themselves, it can be difficult to know how it's observed and why. So we spoke to Mallory Lance of the Ravenous Craft Coven , who explained the traditions behind the vernal equinox.First, who typically celebrates this holiday? Lance says it is derived from religions that worship, above all, nature: "Their practices include venerating the Earth's cycles, respecting the divine feminine, and being in touch with the life, death, rebirth cycle." She adds that, although these faiths are "traditionally deemed 'Pagan,'" others should feel welcome to celebrate, too.The vernal equinox, she explains, is inextricably linked with this cycle of rebirth, as well as the feminine presence of nature. While the fall equinox signifies the Earth's last days before entering winter's hibernation, the spring equinox heralds the end of winter. The two equinoxes reflect death and rebirth, respectively.Lance's peers within the coven are all women in their mid-20s to mid-30s. Aside from a shared love of heavy metal, they're joined by a mutual desire "toreclaim the ancient practice of women gathering and creating." Their spiritual practices aim to honor nature in its purest form, she says.In Pagan and Wiccan traditions, the vernal equinox is also known as Ostara, and these celebrations pay specific tribute to the Pagan goddess of spring . It's believed that when the goddess wakes from a long winter's sleep in March, she thaws the Earth and starts its life cycle anew. This rebirth, so to speak, is what sets the stage for the Pagan holiday Beltane , a fertility festival that occurs one month later. As Lance puts it, during the vernal equinox, "the bounty we're used to associating with spring is not quite there yet — the trees are still bare, the ground is just beginning to thaw." The greenery starting to crop up and the stirring of hibernating animals, she explains, is a sign of greater things to come; it's a time of "enormous potential energy."These elements are all taken into account during the celebrations, which include eating group meals, building altars, and planting new seeds in a garden (or a planter in your apartment's kitchen, or a pot at your desk, whatever works best). Plants bloom, baby birds hatch, and, as legend has it, you just might be able to balance an egg that night.As for Lance, she plans Ravenous Craft's equinox dinner , which takes on a spring theme — specifically, the concept of a return from scarcity. The meal depends heavily on what nature can provide so that the guests can grasp how gradual and rewarding the process of rebirth can be. She says she'll be serving "different foraged ingredients, depending on the abundance of the season." It will be less about feasting and more about observing the changes in nature — and how those changes touch our own lives. This meal, Lance says, "will have an immersive component which seeks to reconnect us with our wild, carnal natures," as it emulates a time when people depended solely upon nature for food.As is the case with any seasonal change, the vernal equinox is a great time to reflect upon the year and what's to come. Not only does the day carry symbolic weight for many people, but it's also one of the two days in the whole year where nighttime and daytime are equal in length . Lance recommends journaling and engaging with yourself quietly after any group celebration you may have.Since the day is mostly about the appreciation of nature, Lance explains that taking advantage of this unique time during the shift in the seasons can be personally fulfilling, no matter what spiritual traditions you follow."We can each personally reflect on the elements we want to let go of, what we want to beckon more of into our lives, and how we can go about making changes toward living more fulfilling and creative lives," she says.No matter how you choose to celebrate it (if it all), Sunday's equinox means that spring's bounty is on its way, which is certainly something everyone can appreciate.