NEW YORK, Aug. 16 (JTA) — Jewish time does not begin in the spring, with the leaf and flower. It begins in the autumn, with the seed. From the harvest, we gather not only food for our tables, but grains and kernels to plant in the coming year. Rosh Hashanah is the new year of the Jewish people not only because we renew our hearts at this season, but because, as fruit turns into seed, we renew the cycle of life. It’s no wonder the sages say God created the world in the autumn. Rosh Hashanah isn’t only the day of the shofar-blast, the day of repentance. It is also the festival of beginning. Nature begins her work of growth and change, mulch and frost, preparing for the spring. So too, we begin our work of growth and change, preparing for an inner rebirth. We may not think of Rosh Hashanah as a festival connected to the earth. Yet consider the Torah portion we read on the first day of the new year. Sarah, the elderly wife of Abraham, conceives and gives birth to Isaac. Even though Sarah is barren, her womb receives new life. The miraculous birth reminds us of the astonishing potential of the earth to give life: as old as it is, as inert as it seems, it is still able to receive each new generation of seed and cause it to grow. Sarah and Abraham, full and abundant in their old age, are symbols not only of the vigor of the Jewish people, but of nature itself. A midrash makes the connection between Sarah’s womb and the womb of the earth even more clear. Rashi, the medieval commentator, tells us: "Many barren women were remembered with her and many sick people were healed on that same day, many prayers were answered with hers, and great was laughter in the world." Later, when Isaac is born, an ancient legend tells us that Sarah’s breasts poured milk out onto the ground and fed many babies along with hers. In both these versions, Sarah’s fertility is connected to abundance throughout the world. Her story reminds us to be grateful for the harvest and for the new seed that will sustain us throughout the coming year. The story we read on the second day of Rosh Hashanah — in which Isaac, child of the covenant is nearly sacrificed, yet spared by God — recalls the many dangers that face the planted seed, and the hope that it will survive these dangers and bring a new harvest in the coming year. Jewish holidays are powerful because they connect the struggles and triumphs of the human spirit to the rhythms of the natural world. Chanukah, festival of courage and faith, comes at a time when the sun’s light has waned and prepares to grow again. Passover, season of liberation, comes in the spring, when living things burst outward in new growth. Tisha B’Av, day of mourning for the Temples, comes in the heat of summer when the crop is under threat from drought. Yet, inside our synagogues, we often forget the natural half of the equation, and thus we lose half the meaning of our sacred stories. If we allow ourselves to reconnect text with earth, we more fully experience the wisdom of our ancestors, and we learn to value the planet that is our home. The greatest gift I’ve received from the Jewish calendar is its awareness of change. The mood of each season, month, week and day is different. In fact, the Hebrew word for year, shanah, is similar to the word shoneh, "changing." It’s even occurred to me that Rosh Hashanah, the "head of the year," could be retranslated as "the beginning of change." As we start out on the path of Jewish time once more, we know we won’t be the same when the new year returns again. The story of Isaac’s unexpected birth teaches us that, just as astonishing changes happen outdoors at every season, change is possible — and even inevitable — within us as well. Rabbi Jill Hammer is the author of the new "The Jewish Book of Days: A Companion for All Seasons" (Jewish Publication Society, 2006) and "Sisters at Sinai: New Tales of Biblical Women" (Jewish Publication Society, 2001).