Have you ever helped plant seeds in your family's garden?

You probably remember placing the seeds in the soil, covering them with more soil, and then watering them. Eventually, the seeds sprouted and became full-grown plants.

Scientists believe seeds have to be placed tightly in the soil so water can flow directly from the soil to the seeds to make them sprout.

But Agricultural Research Service (ARS) soil scientist Stewart B. Wuest (pronounced Weast) says this isn't the case. He says seeds don't need to touch the soil to grow; in fact, they don't even need to touch water to grow!

Wuest explains water vapor is the factor that makes seeds grow. You've probably heard weather forecasters on the radio and television mention humidity and how damp the air is. That's actually water vapor in the air.

A dry seed buried in moist soil will be surrounded by humid air. Since water vapor floats in the air, the seed does not need to touch anything but air to absorb the water it needs to sprout.

You can do your own experiment to see humidity working. Place a dry cracker on the bathroom counter next time you take a hot shower. Whenever there is water in a closed space, evaporating water makes the air humid. The cracker, after absorbing the moisture from the air, will be soggy. Go to the next page.