Monday, March 9, 2009

What Makes Plants Grow Under The Snow?

Wild Plants and Wooly Bears

With the onset of spring, many plants shed dormancy and begin to grow. This happens even to plants that are, and have been all winter, completely buried under snow.

I always had the idea in the back of my mind that some slight bit of sunlight filtered to the ground, thus providing energy for plants. And as hours of sunlight lengthened, plants responded accordingly. But that’s just not so. The truth struck me after a recent blizzard. My office skylight was covered with snow. I sleep in a small loft over the office and the skylight provides a bit of morning light. But not that morning. In fact, my office was black as the inside of a boot. Consequently, I neglected to glance at the clock upon waking up and seeing that it was still dark, immediately went back to sleep.

I got up late, a bit peeved with myself. And then it hit me. If a few inches of snow on my skylight could shut out daylight so completely, surely the many feet that covered the ground did the same. Plants, then, do not grow under the snow in response to sunlight.

So what prompts plants to put on new growth even though they remain in a world of total darkness? For a certainty, this happens all the time. Melting snow reveals all kinds of new growth.

What’s the answer, then? I don’t know. But I find this a thought-provoking question, indeed.

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