Root

A root is the part of a plant that grows underground. Roots have two main jobs. They hold the plant in place, and they pull water and food out of the soil. Almost every plant on Earth has roots, from tiny grasses to the tallest trees.

Roots grow downward, away from sunlight. The tip of each root is covered by a tough little cap that protects it as it pushes through the dirt. Just behind the tip, thousands of tiny hairs grow out the sides. These root hairs are so small you can barely see them. They give the root a huge surface for soaking up water and minerals from the soil.

There are two main shapes of root systems. A taproot is one big main root that grows straight down, with smaller roots branching off it. Carrots, beets, and dandelions have taproots. The carrot you eat is actually one giant taproot. Other plants have fibrous roots, which are many thin roots that spread out in every direction. Grass and corn have fibrous roots. Both shapes work well, just in different ways. Taproots can reach water deep underground. Fibrous roots grab water near the surface and hold the soil tightly.

Some roots store food. A plant makes sugar in its leaves through photosynthesis. It then sends extra sugar down to its roots to save for later. That is why root vegetables like sweet potatoes, turnips, and radishes taste a little sweet. You are eating the plant's stored snack.

Roots can grow surprisingly far. The roots of a single oak tree often spread wider than the tree's branches. The deepest roots ever measured belong to a shepherd's tree in the Kalahari Desert. They reach more than 230 feet underground, deeper than a 20-story building is tall. Desert plants need long roots to find water far below the dry surface.

Roots also help the planet. They hold soil in place so that wind and rain do not wash it away. Without roots, hillsides would slide and farms would lose their dirt. Roots also leave tunnels in the soil when they die. These tunnels let air and water move through the ground, which helps new plants grow.

The next time you pull a weed, look at the roots before you toss it. You are looking at the half of the plant that does most of the quiet work.