There are three harvest festivals in the Pagan Wheel of the Year. The first is Lammas (also known as Lughnasadh) which is the grain harvest (wheat and barley). The second is Autumn Equinox, which is the fruit harvest (particularly relevant in southern Ontario with the huge fruit-growing region of Niagara). It is also the time when day and night are of equal length, but the nights are going to get longer until the Winter Solstice. The third harvest is Halloween (known in Scots Gaelic as Samhain, in Irish as Samhuinn, and in Manx as Sauin), which is when farmers would traditionally slaughter any animals they could not feed during the winter, and salt down their meat for food supplies over the lean cold months.
The Pagan Wheel of the Year was originally based on the cycle of the seasons in Great Britain, which is a bit different than the seasons in Canada, where I live now. For example, when Brits are posting photos of snowdrops on Instagram, Ontario is still covered in snow! It is definitely a good idea to observe the seasons in your locale and adapt the festivals accordingly.
Mythologically, many people associate Autumn Equinox with the Greek myth of Demeter and Persephone, which was the basis of the Eleusinian Mysteries (a Pagan tradition of late classical antiquity). Persephone was abducted by the underworld god Hades, and Demeter’s mourning for her caused the first winter. Then the gods searched for her, and found her with Hades. They negotiated her return to the upper world, but Hades offered her pomegranate seeds, and however many she ate, that would be the number of months she had to stay in the underworld every year. Her annual absence causes Demeter to mourn all over again, hence the return of winter.
I associate Autumn Equinox with the story of Pomona and Vertumnus, goddess of apple orchards and god of the turning seasons. Pomona was courted by several woodland gods, but wasn’t interested in any of them. Then Vertumnus disguised himself as an old woman and came courting her, telling her what a handsome chap Vertumnus was; then she was interested. There are some interestingly queer overtones to this story.
The first person to call the festival “Mabon” was Aidan Kelly in 1974, but this is a misnomer, as Mabon is a Welsh deity or culture hero who has no historical connection with Autumn Equinox. The name has caught on and can be found in many online images of the Wheel of the Year.
In OBOD Druidry, Autumn Equinox is called Alban Elfed, the Light of the Water. I think Alban Elfed is a wonderful name — light and water are a natural pairing and the reflective nature of water does amazing things with light. Water is sacred in most Earth-based traditions, including ancient and modern Pagan traditions, and many of the Indigenous traditions of Turtle Island (North America).
Wiccans often celebrate the Autumn Equinox by re-enacting an aspect of Pagan mythology, and the cooler Fall weather. A typical coven meeting starts with everyone sharing what they have been doing since we last saw each other, and discussing an aspect of life or the significance of the festival we are celebrating. Then we move on to the ritual itself. In Canada, we start with a land acknowledgment. All Wiccans would then cast a circle and call the four sacred directions. Then we perform a ritual drama on the theme of the festival. After that we often do spells for healing. This is followed by a feast.
The purpose of seasonal festivals is to reconnect us with Nature. Wicca (and Paganism in general) is a life-affirming religion with a reverence for Nature. Some people call it a fertility religion, but I disagree – there is more to life than fertility. Rather, it is a religion that celebrates the pleasures of life: consensual sex, food, being with friends, and the beauty of Nature. Both ancient and contemporary forms of Paganism also celebrated same-sex love and gender-variance, and LGBTQ2SIA people are welcome in the Pagan community. It acknowledges that we are part of a cycle of birth, life, death, and rebirth. In Wicca, darkness does not symbolise evil. Darkness and cold are necessary for rest, growth, and regeneration. Death is not evil, but a necessary adjunct to life. If there was no death and dissolution, there could be no change or growth. Suffering is also part of the process of growth; just as a tree is shaped by the wind, we are shaped by our experiences.
If you would like to celebrate Autumn Equinox, you could gather fruit such as blackberries, pomegranates, apples, peaches, and persimmons, and share them with your friends. The dark half of the year, when the evenings and nights are longer, are a time for introspection and creativity, so now is a great time to start creative projects like knitting, crochet, and baking.
You can also create your own ritual, celebrating the cooler weather, the drawing-in of the nights, your personal harvest, fruit, and creativity. There are many templates available online for solo and small-group rituals, or you can create your own.