How Seeds Germinate

A free interactive lesson on seed germination for Class 5 — what's inside a seed, why seeds don't need light to germinate, and how water, warmth and oxygen trigger the sleeping embryo to wake up. Based on NCERT Class 5 Seeds and Plants. Includes quiz.

Class 5 ScienceClass 5 / Grade 5Ages 7–10
Lesson
🌱 How Seeds Germinate
A tiny seed holds an entire plant inside.EmbryoSeed = embryo + food storeWeeks later — a whole plant!Germination = seed waking up to grow.

Inside a tiny mango seed is everything needed to grow a full-sized tree. The seed is not dead — it's dormant, sleeping. Given the right conditions, it wakes up, pushes a root into the soil, raises a shoot into the air, and begins to grow. This awakening is called germination.

What's inside a seed?

Every seed contains three main parts. The embryo is the tiny baby plant — it has a miniature root (radicle) and shoot (plumule). The cotyledons (seed leaves) store food to fuel the embryo until it can photosynthesise. The seed coat (testa) is the hard outer covering that protects the embryo from drying out and physical damage.

Seeds with one cotyledon are called monocots (e.g. wheat, maize, rice). Seeds with two cotyledons are called dicots (e.g. beans, peas, sunflowers). This difference affects the pattern of leaf venation and other plant structures.

Conditions for germination

Three conditions trigger germination — not light:

  • Water — seeds absorb water through the seed coat (imbibition), which activates enzymes that break down stored food into sugars the embryo can use for energy.
  • Warmth — most seeds germinate best between 15–25°C. Cold temperatures slow enzyme activity; extreme heat denatures them.
  • Oxygen — the germinating embryo needs oxygen for cellular respiration to generate energy for growth.

Light is not required for germination — seedlings can germinate underground in complete darkness. Light only becomes essential later for photosynthesis.

The germination process

When water enters the seed, the embryo swells and the seed coat splits. The radicle (embryonic root) emerges first, growing downward (guided by gravity). Next, the plumule (embryonic shoot) pushes upward toward the surface. The cotyledons may emerge above the soil (epigeal germination, e.g. beans) or stay below (hypogeal germination, e.g. peas) depending on the species.

Once the seedling reaches light, its first true leaves unfurl and photosynthesis begins — the plant can now make its own food.

Frequently asked questions

What three conditions does a seed need to germinate?

Water, warmth, and oxygen. Water activates enzymes inside the seed. Warmth ensures enzyme reactions happen at the right speed. Oxygen is needed for the embryo's respiration to generate energy for growth.

Do seeds need light to germinate?

No — seeds do not need light to germinate. They contain stored food in the cotyledons to fuel early growth. Light only becomes essential once the seedling emerges and needs to photosynthesise.

What is the difference between a monocot and a dicot?

Monocots have one cotyledon (seed leaf) — examples include rice, wheat, and maize. Dicots have two cotyledons — examples include beans, peas, and sunflowers. This difference also affects leaf vein patterns and other structures.

What part of the seed grows first?

The radicle (embryonic root) emerges first, growing downward. Then the plumule (embryonic shoot) pushes upward toward the surface. The root emerges first to anchor the plant and absorb water before the shoot reaches light.

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