Over 200 years ago, Carolus Linnaeus, a Swedish botanist, told the time of day with a garden clock. He simply planted a circular garden made up of plants, which bloomed at different times of the day.

Some plants flowered at sunrise. Others flowered at eight o'clock. Still others flowered at noon, mid-afternoon and dusk. By arranging the flowers according to the time their blossoms opened, Linnaeus created a garden clock.

The opening and closing of flower blossoms is called nastic movement. As the Sun warms the petals of a blossom, the pressure inside the cells of the petal increases. This pressure is called turgor pressure. Like an inflatable plastic toy, individual cells become rigid as the pressure builds and the flower unfolds.

As the air begins to cool at Sunset, the cell pressure inside each blossom decreases and the flower closes.

By planting flowers, which bloom at different times of the year, you can grow a calendar garden, which reveals the date. By choosing your flowers carefully, first one flower and then another will bloom as the amount of sunlight changes during the spring, summer and fall.

©Copyright 1998 Elizabeth Beckett, Holly Bernitt, and Vishwa Chandra.