Soil Fertilizer

Contributor: Hannah Brooks. Lesson ID: 12449

Plants need to eat, just like you do. However, they don't eat like you do. They can't go out to eat, so the food has to come to them. Learn what fertilizer is and why plants like it although we don't!


Earth Science

learning style
personality style
Grade Level
Intermediate (3-5)
Lesson Type
Dig Deeper

Lesson Plan - Get It!

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What do you eat? How do you eat? Have you ever wondered how and what plants eat? You may not like what you find out, but plants love it!

Many farmers use fertilizers to improve the nutrients in the soil.

This helps crops and plants grow faster and larger. So, what exactly is a fertilizer?

If you missed or would like a refresher on the three previous Soil lessons, find them in the right-hand sidebar under Related Lessons.

fertilize plant

Fertilizer is a substance that provides nutrition for plants. What kind of nutrition do you need each day? What do you like to eat? Plants need a little bit of nitrogen, phosphorus, and potassium. These elements can be added to the soil through different means. There are a couple different kinds of fertilizers that you can use to help plants grow. Some farmers use organic matter, like manure from cows, as a fertilizer. This helps the plant by providing nutrients like nitrogen and phosphorus.


Manure is a natural way to provide plants with extra nutrition! It doesn’t harm the soil, but can run off into bodies of water. This can drain into our drinking supply — Ick!

The most common type of fertilizer is called synthetic, or inorganic, fertilizer, because it is man-made. Scientists combined elements to create a substance that can easily be added to soil for plant growth. This mixture has a lot of the nutrients soil needs, with high nitrogen, phosphorus, and potassium values.


Fertilizers can be extremely helpful in increasing the amount of vegetables and plants we can grow to feed people. They allow plants to grow larger and faster!

tomato plants

That helps us feed the growing population of the Earth! However, fertilizers can damage the soil and environment. When a farmer uses too much fertilizer, it can build up in the soil. This causes the soil to dry out, meaning that more water must be added for the plants to grow.

wheat field

Fertilizer can also run off when a heavy rain moves through. The rain water pushes the nutrients toward rivers and lakes. Once in the rivers and lakes, it can harm wildlife and contaminate our drinking water.


Fertilizers can be really helpful in growing plants and crops. They add necessary nutrients to the soil, helping plants grow larger and stronger. Fertilizers can be organic — made of matter from living things — or inorganic.

There are some downsides to using too many fertilizers. It can cause harm to the soil and our water supply!

Create a two-column chart to compare the benefits of fertilizers to the negative impacts. Put the benefits in one column, and the consequences in the second. Share this with a parent or teacher, and ask what thoughts they would like you add to your chart.

In the Got It? section, answer some questions about the types of fertilizers.

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