Plant Nutrients

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What are the most important plant nutrients to grow a healthy plant? How can I ensure my plants get these nutrients?

Nitrogen, phosphorus and potassium are the big three primary nutrients. Secondary nutrients (calcium, magnesium and sulphur) and trace elements (iron, manganese, zinc, copper, boron, molybdenum and chlorine) are also crucial for healthy plant growth. Plants require all nutrients in the right amount for healthy plant growth. Most of these nutrients can be found in healthy soil. It can also be worthwhile to use a fertilizer to make sure plants receive all required nutrients.

I have spent multiple hours researching this article from reputable sources [1,2,3,4,5,6] so that you don’t need to. Read below to find my research results.

Table of Contents

NPK – The Three Main Building Blocks

Secondary Nutrients

Trace Elements

What is nutrient deficiency?

How to solve nutrient deficiency?

NPK – The Three Main Building Blocks

The three main nutrients all plants require are nitrogen (N), phosphorus (P) and potassium (K).

Fun fact: 95% of a plant’s weight is made up of hydrogen, oxygen, nitrogen and carbon!


Nitrogen is found in plant cells, proteins, hormones and chlorophyll.

It helps with:

  • Plant cell formation
  • Protein, hormones and chlorophyll growth
  • Good stalk growth


  • improves energy transfer from sunlight to plants
  • Strengthens the root system
  • Aids in seed creation capacity
  • Improves seed resistance
  • Increases pest prevention
  • Improves flowering and blooming
  • Strengthens a plant’s tissues
  • Improves flavors in edibles and vegetables


  • Helps form and move plant starches, sugars and oils
  • Can improve fruit quality
  • improves root and seed production
  • Increases ability to tolerate extreme temperatures
  • Helps resist disease

Secondary Nutrients

The main secondary nutrients plants require are calcium, magnesium and sulphur.


Calcium helps:

  • Keep healthy plant roots
  • Increase new root growth
  • Increase Leaf development
  • Strengthen cell tissue
  • Neutralize acidity


Magnesium is a key component of chlorophyll and aids in:

  • Photosynthesis
  • Chlorophyll growth
  • Regulating phosphorus intake
  • Encouraging CO2 absorption
  • A plant’s healthy dark green color
  • Formation of sugars, proteins, oils and fats


Sulphur makes up amino acids in plant proteins and improves:

  • Energy producing processes in plants
  • Flavor and odor components of some plants, e.g. onions, cabbage

Trace Elements

The trace elements include iron, manganese, zinc, copper, boron, molybdenum and chlorine. Although they are trace elements, a deficiency in any one of these can have a huge effect on plant growth.


Iron helps:

  • Manufacture chlorophyll (the substance that gives plants their green color)
  • Aids in other biochemical processes


Manganese helps:

  • with chlorophyll production


Zinc aids in:

  • Development of enzymes and hormones
  • Chlorophyll production


Copper helps:

  • Form chlorophyll


Boron helps with:

  • Cell development
  • Regulating plant metabolism (i.e. creating energy from plant food)
  • Protein creation in vegetable plants
  • Cell wall development in vegetable plants
  • Carbohydrate (sugar) metabolism
  • Sugar translocation in vegetable plants
  • Pollen grain germination in vegetable plants
  • Pollen tube growth in vegetable plants
  • Fruit and seed development in vegetable plants


Molybdenum deficiency often results in stunted plant growth. It helps:

  • Plants use nitrogen


Chlorine is:

  • Needed for photosynthesis

What is nutrient deficiency?

Nutrient deficiency happens when plants do not receive the nutrients they require. This can lead to slower growth, greater chance of disease and unhealthy plants, which reduces a crop’s yield. It is worthwhile to note that too many nutrients can also harm and kill plants, so a balance must be found. A plant’s growth is limited by the nutrient that is in shortest supply.

Some common nutrient deficiency symptoms are:

  • Little or no growth
  • Dead tissue at leaf tips
  • Yellow or dead leaves on only one side of a plant
  • Leaf yellowing and white color between leaf veins

How to solve nutrient deficiency?

High quality soil

Using high quality soil tends to be the easiest solution. High quality soil contains most, if not all, of the required nutrients. If you are a novice gardener, it can be a good idea to plant in a pot or a container.

If you decide to grow directly in the soil in your yard, it’s a good idea to test your soil quality. A soil test kit such as the Luster Leaf Rapitest Soil Test can make it simpler to get started.

Make sure to check for disease, insects, herbicides or soil that is too compact. Compact soil may lead to the plant roots to not receive enough oxygen.


It is also useful to use fertilizer sparingly. Fertilizer always contains an NPK ratio, e.g. 6-6-6. This means that the fertilizer contains 6% nitrogen, 6% phosphorous and 6% potassium. Some fertilizers may have higher nitrogen ratios, e.g. 20-6-6. If you want good rooting and post-transplanting care, a fertilizer with a ratio of e.g. 6-20-20 may be appropriate. A good flowering ratio could be e.g. 6-20-6.

Fertilizer is either synthetic, pre-packaged or chemical. Synthetic or chemical fertilizer may have negative environmental impact. Organic fertilizer is better for the environment, but does not act as quickly as synthetic or chemical fertilizer.

Make sure to buy a fertilizer that contains all of the elements, not just NPK. A recommended fertilizer is Espoma Organic Home Meal fertilizer.

Remember that using too much fertilizer can lead to fertilizer burn, which negatively impact plant growth too. If you follow the recommendations for quantity and fertilizer frequency on the fertilizer label, you should be good to go.


High-quality soil is super important. I tend to use good quality soil for the bottom 75% of my container and then flower or herb soil for the top 25%, seeing as the herb soil is more expensive.

I personally like water soluble fertilizers, as they are easy to apply and lets me fertilize and water at the same time. Granular fertilizers can work just as well. For simplicity, you could use a balanced fertilizer for all stages of growth (e.g. NPK ratio of 2-2-2). You could also use a growth-focused fertilizer (higher N and K values) in the beginning and switch over to a flowering fertilizer (e.g. NPK ratio of 6-20-6) once your plants start flowering. It is slightly more complicated, but will most likely lead to better results.

Make sure to follow the instructions on the fertilizer label when it comes to quantity and frequency. It may sound complicated, but as long as you don’t apply too much fertilizer, there is not too much that can go wrong.

Take a stroll to your local gardening supply shop, ask for their advice and get started today!

To learn more about gardening, feel free to read my intro to container gardening and/or container vegetable gardening.

Photo of author


Every since studying engineering, Bjorn has been interested in how technology can help grow plants quicker.

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