Sometimes called Eostara or Ostara, from which the word Easter is derived, the Vernal Equinox -- when the position of the earth balances night and day evenly -- is the beginning of spring.
The Wheel turns again and with this turn comes the Vernal Equinox or Eostara. At this time the hours of daylight and night are balanced against each other. After this time, and until the Autumnal Equinox, daylight will have the ascendent [stet] influence. The goddess now wears the aspect of the Maiden of Spring and meets the young god, now the Youth of Spring, who was born into the world at Yule. Together, the coupling of masculine and feminine energies will plant the seeds of life and growth upon which all the continued survival of the world depends.
. . .A sabbat of balance and beginnings. A traditional time to prepare for future planting and bless the seeds of physical, spiritual, and ritual gardens.
So the Vernal Equinox is celebrated as a time of germination. It is the early spring when things first begin to visibly sprout and grow. It is also one of those crystal clear correlations of paganism and it's hybridization with, or usurpation by, early Catholicism. In Welsh it's Gwyl Canol Gwenwynol.
The Spring Equinox defines the season where Spring reaches it's apex, halfway through its journey from Candlemas to Beltane. Night and day are in perfect balance, with the powers of light on the ascendancy. The god of light now wins a victory over his twin, the god of darkness. In the Welsh Mabinogion, this is the day on which the restored Llew takes his vengeance on Goronwy by piercing him with the sunlight spear. For Llew was restored/reborn at the Winter Solstice and is now well/old enough to vanquish his rival/twin and mate with his lover/mother. And the great Mother Goddess, who has returned to her Virgin aspect at Candlemas, welcomes the young sun god's embraces and conceives a child. The child will be born nine months from now, at the next Winter Solstice. And so the cycle closes at last to begin anew.
The customs surrounding the celebration of the spring equinox were imported from Mediterranean lands, although there can be no doubt that the first inhabitants of the British Isles observed it, as evidence from megalithic sites shows. But it was certainly more popular to the south, where people celebrated the holiday as New Year's Day, and claimed it as the first day of the first sign of the Zodiac, Aries. However you look at it, it is certainly a time of new beginnings, as a simple glance at Nature will prove.
There are two holidays of Christianity which get mixed up with the Vernal Equinox. The first, occurrs [stet] on the fixed calendar day of March 25th in the old liturgical calendar, and is called the Feast of the Annunciation of the Blessed Virgin Mary. 'Annunciation' means an announcement. This is the day that the angel Gabriel announced to Mary that she was 'in the family way'. Naturally, this had to be announced since Mary, being still a virgin, would have no other means of knowing it. The Church picked the Vernal Equinox for the event because it was necessary to have Mary conceive the child Jesus a full nine months before his birth at the Winter Solstice (i.e., Christmas, celebrated on the fixed calendar date of December 25). Mary's pregnancy would take the natural nine months to complete, even if the conception was a bit unorthodox.