Nitrogen

Nitrogen is essential for plant growth.

When plants do not get enough oxygen, their growth is stunted. Their leaves are pale and unhealthy-looking.

If a plant that with this sickly appearance is given readily available nitrogen it will start to grow quickly. Its leaves will be larger and darker green. Overall, the plant will be stronger.

Sometimes, however, supplementing with nitrogen can be harmful.

In some instances, it is good to supplement with nitrogen so that plant growth will increase, for example, when you are growing lettuce or spring cabbage.

However, in many instances, giving too much nitrogen can be harmful.

Plants only take up other nutrients, such as potash and phosphoric acid, according to how much they are growing. The amount of nitrogen determines how much the plant grows.

When there is too much nitrogen, the plant grows in a sappy, luxuriant manner. The plant is slow to mature and does not ripen well. It becomes susceptible to attacks by fungus.

Therefore, if a plant seems healthy, strong and is growing well, you should not add nitrogen unless you also add other nutrients to make sure the plant food is well balanced.