How do dahlias know...

[bazfaz]

...when it is time to start growing? When I lived in England I grew dahlias. Each autumn I would lift the tubers, hose the earth off, let them dry a few days. Then I would wrap each tuber is newspaper, put the wrapped tubers in cardboard cartons, then place the cartons in a room that had no exterior light. There they sat, in total darkness, all through the winter. Come April they would send out shoots. How did they know it was time to start growing again?

[bjd]

They asked the tulips. Didn't you hear any murmuring in that dark room?

[Deleted]

Such mysteries of nature have always intrigued me as well.