How Can Magnets Accelerate the Growth of Radish Seeds?

Tropism

• Tropism is movement toward or away from a stimulus. In plants, think of how the sunflower grows so it faces east, following the sun, called heliotropism. Phototropism is the movement of plants toward a light source. It is possible to manipulate a plant to follow light sources. When it comes to gravity, the phenomenon is geotropism, or gravitropism. Geotropism is the movement of plants toward and away from gravity. It is the reason that roots grow down, toward the gravitational pull. Magnets help stimulate the growth by mimicking gravity.

Magnets and Geotropism

• Place a magnet at the bottom of a pot and plant radish seeds. The plants will grow faster than those without a magnet. The magnet makes gravity feel stronger to the plant. The plants feel the Earth's gravity and the roots grow toward it. Add a magnet and the plant feels a stronger "gravity," as if closer to the center of the Earth. Just as the Earth is a giant magnet that pulls everything in, the magnet pulls the roots of the plant toward it. Since the pull is stronger with a magnet, the plant reacts by growing faster. The magnets strengthen the geotropism.

Growing Radishes with Magnets

• Use strong magnets to help radishes grow faster, such as neodymium magnets, a type of rare-earth magnet, or alnico magnets, also known as cow magnets. Weaker magnets, such as those used for refrigerator magnets, will have no effect on the plant. Fill the pot with soil and push the magnet into the middle. Plant the seeds so they are a few centimeters away from the magnet. Experiment with the polarity of the magnet. Place some magnets with north facing up and others with south to see which polarity has the greatest effect on the seeds. Also experiment with placement of the magnet, whether below the seed or to the side. Try growing other plants with magnets and see how they grow.

Fun Fact

• While scientists know that gravity plays a part in which direction plants grow, they do not know how plants recognize up from down. How do plants feel gravitational pull? Scientists believe plants have two possible ways, according to NASA. Either the pressure on the plant cells from gravity signals the correct direction or gravity pulls down the starch grains in the plants like a magnet. Experiments to find the answer to this conundrum include growing plants in space and creating "gravity" using magnets.