How Do Fertilizers Affect Plant Growth?

Have you ever noticed how your plants become weaker toward the end of the growing season? This is due to the loss of nutrients. There are many reasons for this, whether it’s a disease, insect damage, or the weather changing, but the most common is over-fertilization. Over-fertilization can be done by hand or with a small amount of fertilizer in a cup.

We will talk about why most people over-fertilize, what different fertilization methods involve, and how to make it less likely to over-fertilization.

What is fertilizer 

Fertilizer is used on plants to promote growth. Plants need nutrients to grow. The nutrients that plants need are called macronutrients. These are present in fertilizers like nitrogen, phosphorus, potassium, and calcium.

 Fertilizers can be divided into three groups:

  •  Organic fertilizers (manure and compost)Animal feces, plant or animal waste, and other materials are all types of garbage.
  • Mineral fertilizers (phosphorus and potash) are Mined from the environment and crushed or chemically treated.
  • Industrial fertilizers (ammonium phosphate, urea, ammonium nitrate) Biological reactions produce industry by humans.

Chemical Properties of Fertilizers

Fertilizers consist of various chemical compositions. For example, synthetic fertilizer has many advantages, including high concentration and stable quality. 

However, synthetic fertilizer has some disadvantages, such as toxicity, environmental pollution, and economic loss.

Source of organic fertilizers

Organic fertilizers derived from naturally occurring organic materials tend to be more complex and less predictable than inorganic fertilizers. They are usually less concentrated, so they must be mixed with other materials at lower rates. 

Source of inorganic fertilizers

Inorganic fertilizers, on the other hand, are relatively easy to produce. The abundance of mineral deposits and the ease with which earth minerals can be extracted from non-living material has made this type of fertilizer very economical. 

These fertilizers are composed almost entirely of inorganic materials and contain only a small percentage of organic compounds.

Effects of Fertilizer on Plants

Fertilizer consists of a blend of three main nutrient components: nitrogen, phosphorus, and potassium (N-P-K). All three are critical for plant growth at various levels and combined to bring plants to their fullest potential. However, they are not universally found in all soils.

Sometimes soil fertility is so low that all three components are imbalanced, and no proper amount of nutrients can be acquired. The soil you have will determine the kind of fertilizer you will use too.

Composition of Fertilizer

Fertilizers are composed of various chemical components, which can vary depending on the source and intended use of the fertilizer. The more complex fertilizers contain nitrogen, phosphorus, and potassium.

The three numbers printed on the side of all garden fertilizers tell you the percentage of nitrogen, phosphorus, and potassium in the product.

An example of a 100-pound bag of fertilizer is 25-20-15, which contains 25 pounds of nitrogen, 20 pounds of phosphate, and 15 pounds of potassium. The filler material, usually organic, makes up the remaining 40 pounds.


Nitrogen is possibly the most important of the three. The relationship between nitrogen and food production is well established. The major use of nitrogen is in the formation of proteins, which are essential for proper growth, reproduction, and development. Nitrogen is also important for plant photosynthesis and the biosynthesis of unique plant hormones and amino acids. 

The problem is that nitrogen is also needed for the formation of ammonium ions. Nitrogen does not exist in pure form but rather as a complex of nitrogen ions. In order for leaves and stems to maintain their vibrant green color, nitrogen is required.

Photosynthesis is promoted because of this. The quantity of nitrogen present in any fertilizer is always expressed as the first of the three-number combination on the label. 15-20-12 contains 20 percent nitrogen.


Phosphorus is the second major nutrient in fertilizer. Phosphorus is needed for the formation of DNA and RNA, as well as the production of ATP, the body’s main source of energy. 

Phosphorus is also important for root development, healthy growth, and for the production of sucrose. When used frequently after planting and again during flower blooms, phosphorus is beneficial to develop strong roots and abundant fruit.


Potassium is the key nutrient in all fertilizers. Potassium is needed for healthy growth and for the formation of sugar. Potassium is also important for flower and fruit development.

Potassium, like phosphorus, has all three numbers on the label, indicating that it is included in every 15-20-12 fertilizer bag. Potassium is a component of carbohydrates and plays a crucial role in carbohydrate metabolism.

What happens when you don’t use fertilizer?

Fertilizers used correctly will feed your plants, and plants will love you. Use too much fertilizer; your plants will not get enough food. But if you do not fertilize when necessary, and the excess fertilizer builds up in the soil, some serious negative effects can happen.

You may notice your garden looks great for a few weeks but when you went to plant again and found that your tomatoes have no roots! Why? They were wilting because they lacked water. This is why it is so important to use fertilizer when you need it, but never too much.

Pros of Synthetic Fertilizer (inorganic fertilizer):

  • Prevents soil-borne diseases (e.g., Phytophthora root rot).
  • Promotes lush foliage while reducing dependence on water and minimizing the chance plants will wilt during hot weather.
  • Prevents chlorosis (a.k.a., yellowing) of leaves, a sign of iron deficiency, which is often caused by low manganese or other trace metals.
  • Increases the nutritional quality of soils and prevents soil depletion.
  • Prevents nutrient imbalances, which can occur due to different fertilizer types, materials, and application methods used.
  • Prevents nutrient deficiencies.
  • Improves water retention and root development. (Manganese).
  • Prefers low pH values, which make it less likely to burn the

Cons to using a synthetic fertilizer

Synthetic fertilizer does not improve one element of a plant’s ecosystem. Synthetic fertilizers do not alter soil type or feed the microorganisms that help plants’ root systems keep healthy. However, Synthetic fertilizers can be a good option for your garden.

Pros of Organic Fertilizer

There are many benefits of using organic fertilizers over synthetic ones.

  • Organic fertilizers are less likely to contain toxic chemicals that can harm you and your family.
  • They provide your plants with the necessary nutrients they require for growth.
  • Organic fertilizers are prepared from plants, not petroleum products like urea and ammonium nitrate.
  • Organic fertilizer usually contains materials that improve soil texture and aeration.

Cons of using Organic Fertilizer

Fertilizers cannot target nutrient deficiencies. It is important to use the right kind of fertilizer for your plants. Many people assume synthetic fertilizers are cheaper than organic fertilizers. But you can find them either way at the store. The difference is that synthetic fertilizers can be made from fossil fuels, but organic fertilizers can be made from various sources, including plants.

Which fertilizer should you use?

Fertilizer is the key to ensuring cost-effectiveness and soil health balance. You can use both types of fertilizer for different types of gardens.

If you are only growing vegetables, you should use a balanced fertilizer designed for vegetables and herbs. This fertilizer contains potassium, phosphorus, and calcium. It is commonly referred to as a vegetable fertilizer. It will be formulated for plants like tomatoes, cucumbers, etc.

If you are only growing flowers, like flowering plants or bulbs, then you should use a balanced fertilizer specifically designed for flowering plants and bulbs. This fertilizer contains potassium, phosphorus, nitrogen, and some trace element(s). It is commonly referred to as a flower fertilizer.

Many flower gardens only use 1 or 2 types of flower fertilizers because they provide all the nutrients these types of plants need without adding too much extra in that the plant cannot utilize its nutrients simultaneously.


How does fertilizer affect plant growth scientific method?

NITROGEN, PHOSPHORUS, and potassium are essential nutrients that help plants grow new cells and produce food.

What factors affect plant growth experiments?

Several factors affect plant growth, such as light, water, temperature, and soil nutrients. Light is essential to photosynthesis, or the process plants use to gather the energy they need to grow.

Water is also very important in helping plants grow and produce food.

How do chemical fertilizers affect plant growth?

Most chemical fertilizers are soluble fertilizer that is applied to plant roots. The fertilizers help plants absorb water and nutrients, which helps them exchange them with the root system. Chemical fertilizers increase crop production by increasing soil fertility, decreasing pesticide use, weakening pesticides, and polluting air and water.


In this article, we can see how fertilizer can be used to improve the growth of our crops that, when applied correctly, do not affect our wildlife. It makes our environment better and can be used to help other living things. It helps to produce more food and helps us live longer. Overall, fertilizer plays a huge role in our environment, and we must ensure it is used correctly. I hope you like the article. If you have any questions, please feel free to comment. Have a nice day