Seed Germination and Its Conditions

1What germination is

A seed holds a tiny baby plant, a store of food for it, and a tough seed coat that protects it. When the baby plant wakes up and starts to grow, we say the seed germinates. This is called germination.

2What a seed needs to germinate

1. Water. The seed soaks up water and swells. Water softens the seed coat and wakes up the baby plant.
2. Air. A seed is alive and needs oxygen from the air. Seeds left under water, or in soil that is flooded, cannot get air, so they rot.
3. Warmth. Seeds need a suitable temperature. In a very cold place they wait and do not grow.
4. A healthy, living seed. A seed that is broken, eaten by weevils, too old or cooked will never grow. Roasted groundnuts will never become plants!

3Surprises

• Most seeds do not need light to germinate: they start growing in the dark soil. But once the young plant's green leaves open, it needs light to make its food.
• Seeds do not need soil to germinate. They use the food stored inside them, so they can start growing on damp cotton wool or tissue. The plant needs soil later, to keep growing.

4Experiment: which beans will germinate?

Put 3 bean seeds on cotton wool in each of four jars:

5Watch a bean grow

Line a clear jar with damp tissue and push a bean between the tissue and the glass, so you can see it. Keep the tissue damp. Every day for two weeks, measure the bean with a ruler and write down what you see: on which day did the root appear? The shoot? The first leaves?

Try it yourself

Try each one first, then tap Show answer to check.