Seeds are formed from the fruits of plants. Seed contains a small plant inside it called as embryo.    Baby plant sprouts out of the seed when conducive environment is provided. This process by which a plant emerges from the seed is called as seed germination.

The germination of the baby plant from the seed is affected by various internal and external factors.

Internal factors:

Different seed is of different nature. The nature of the seed widely affects the germination process

Dead seed:

It is not that all the seeds will develop into plants. Dead seeds do not possess any embryo inside. These seeds hence will not germinate even under perfect environment.

Dormancy:

Dormancy period is the idle period; the seed requires preparing for germination. Dormancy helps the seeds to preserve the embryo within. The seeds with smaller dormancy period cannot be preserved for a longer time. Dormancy usually depends on the seed coat structures. Seeds with thick coats usually take a longer time to germinate than those with thin coats. The thick coat prevents water from entering the seed fast, thus inhibiting germination. But these thick coated seeds can be preserved for a long time from dying. Usually vegetable seeds germinate very fast. But lotus seeds take a longer time to germinate.

External factors:

Like plant growth, seed germination is also affected by various external factors like light, water, air and temperature.

Water:

Water is the key factor that aids the germination of a seed. A seed can be prepared for germination by moistening. Care to be taken not to over soak the seed fully in water. When water penetrates the seed, the seed bulges. When the seed coat softens, the seed breaks and the seedling emerge out. Seed usually have some amount of stored food inside. When treated with water, this food is supplied to the seedling, aiding germination.

Air:

Air plays a vital role in germination. Seed should get ample oxygen for germination. Inadequate oxygen supply will inhibit the germination, leading to seed death. Thus seed should not be buried deep into the soil, as it hampers the air supply and hence the germination.

Temperature:

Different species of seeds require different temperature for germination. Most of the seeds require a temperature little above the room temperature to germinate. Some seeds require cool climate for germination. Exposing the seeds above or below these temperatures prevent the seeds from germination. Hence some seeds germinate during summer season and some during winter.  Conducive temperature helps to break the dormancy period of a seed. Vegetable seeds germinate slightly above the room temperature. Radish and spinach seeds prefer winter season for germination.

Light:

Seed germination is not mostly affected by light. But some seeds belonging to wild plant species require bright light to germinate. These seeds start germinating when exposed to forest fire. But for seeds, presence of excess light hinders germination. Such seeds germinate only after burial in the soil.

Soil:

The nature of the soil in which the seeds are buried also affects the growth of the seedlings. A seed buried in light, loose soil germinates faster. Garden soil rich in nutrients are best suited for healthy germination.

In short, good quality seeds when exposed to water, air and sunlight appropriately, germinate faster into a healthy plant.