Pull up a weed and look at the bottom. You will see thin, twisty strings. Those are roots. Most of the time they hide under the ground, so we forget about them. But a plant could not live without them.
Key idea
Roots hold the plant in the ground and take in water and nutrients from the soil.
Why it works
Water is in the soil, so the roots grow down to reach it. They spread out wide, like fingers holding on, so wind and rain cannot knock the plant over. The water they drink goes up the stem to the leaves.
Worked example: Let's think it through
Sam sprays water on a plant's leaves, but the soil stays dry. Will the plant get the water it needs?
- Where does most of a plant's water come in? Through its roots.
- The roots are in the soil.
- The soil is still dry, so the roots have nothing to drink.
Answer: No. Sam should water the soil, so the roots can drink.
Common mistake
Many children think roots only hold the plant up, or that a plant drinks through its leaves. Holding on is one job. Drinking is the other big job, and most of a plant's water comes in through its roots.
For the grown-up. Some roots also store food for the plant, like carrots, beets and radishes. A potato grows underground too, but it is a stem, which you will meet in Plant Parts We Eat.