Why do seeds need to travel away from their plant?

Have you ever held a fluffy dandelion, felt its soft white puff, and blown its seeds into the breeze? Off they drift, far across the grass.

Maple seeds spin away like small helicopters, and burrs ride along on a dog's fur. So many seeds leave their plant behind. Why do seeds need to travel away from their plant, instead of dropping right beside it?

Let's picture a big oak tree in autumn. It drops an acorn straight down beside its own trunk, and in spring the acorn sprouts in the soil. Up comes a seedling, which means a baby plant just growing out of its seed.

A seedling makes its own food in its green leaves, and its leaves need sunlight to do that. So the young oak stretches its first small leaves up toward the light.

High above it spreads the big oak's canopy, which means the roof of leaves at the top of a tree. Those leaves catch the sunlight first, so the ground underneath lies in cool, deep shade.

Under the canopy, the seedling catches only thin spots of light. With so few sunbeams, it makes only a bit of food, and it grows slow and thin.

Down in the soil, the big oak causes a second problem. Its long roots spread out wide under the ground all around its trunk. When rain soaks in, where do you think most of that water goes?

Into the big tree's roots! They drink up most of the water first, so the seedling's short roots find only a few sips. The young oak stays thirsty as well as hungry for light.

Now picture another acorn that a squirrel carries far across the meadow and tucks into the ground. Over this spot, no canopy blocks the sky, and no big roots drink up the rain.

This seedling gets sunshine on its leaves all day and the whole patch of rain-soaked soil to itself. It makes plenty of food, drinks its fill, and grows tall and strong.

Seedling, canopy. A big plant's canopy blocks the sunlight and its roots drink the water right beneath it, so its seeds need to travel away to a spot where each seedling gets enough of both.

The next time you blow a dandelion, you can wish each floating seed a sunny spot of its own. Rest well, and keep wondering.