In a way, the calendar hones what folklore and farmer's hunches suggest. Each constellation of the zodiac, for instance, has a relationship to earth, air, fire or water. Likewise, each plant. Root crops, such as radishes, are earth. Leaf plants, such as lettuce, are water.
Flowers are air.
Fruit, which requires warmth to mature, is fire. The moon charts the course. How we time sowing and gardening activities can enhance these influences or hinder them. Mainstream horticulture has not exactly embraced the notion. Rather than feeling overwhelmed by all the chores, he focuses only on ones appropriate to the day.