|
Have you ever helped plant seeds in your family's garden? You may remember placing the seeds in the soil, covering them with more soil, and then watering them. Eventually, the seed sprouted and became full-grown plants. Scientists believed seeds had 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 says that water vapor is what makes seeds grow. You've probably heard weather forecasters on the radio and the 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. To prove his theory, Wuest designed two experiments at ARS' Columbia Plateau Conservation Research Center, Pendleton, Oregon. In one experiment, he placed a layer of fiberglass cloth between the seeds and the soil to prevent the seeds contact with water. Despite the cloth barrier, the seeds still sprouted! In the other experiment, Wuest hung some seeds in the air above water. He determined that contact between rising water vapor and the seeds was enough to make them sprout. So, don't worry next time you're in the garden and can't remember where you've planted the seeds for your favorite veggie. As long as the water is close by the seeds, you'll see them sprouting sooner or later. Click to read a longer article about Wuest's water vapor research. - By David Elstein, Agricultural Research Service, Information Staff Back to main page/
Return home |
