Types of Fertilizers


Fertilisers provide plants with essential elements needed for optimal growth. The minerals in fertilizer, are absorbed through the plants root system.

Fertilisers generally contain primary nutrients, essential to creating the perfect crops for harvesting as well as plant growth and flower blooming such as nitrogen (N), phosphorus (P) and potassium (K). Nitrogen (N) and phosphorus (P) for optimal root development, and potassium (K) for overall plant health.

The proportions of these elements in a fertiliser are often shown on their packets or bottles as N:P:K If you aren’t familiar with what they mean the numbers detail the percentage of each element in what is known as the product’s guaranteed analysis. There are also some secondary nutrients that aid plant growth, mentioned below. Fertilisers can increase crop yields and are widely used in agriculture. Fertilisers can come in a few different options that will be made up of either:

  • Animal products
  • Bio-solids
  • Chemical compounds
  • Minerals 
  • Plant based products
  • Urea 

Some crops may require more or less of each nutrient so it is very useful to first understand your plants needs and preferred soil composition, beforehand. You can then check the pH of your soil, which will indicate whether the soil is acidic, neutral or alkaline. This will assist with selecting the correct nutrient ratio, if using shop bought fertiliser.

There are also secondary nutrients that may be required such as; calcium (Ca), magnesium (Mg), sulfur (S), boron (B), copper (Cu), iron (Fe), chloride (Cl), manganese (Mn), molybdenum (Mo), and zinc (Zn).

Organic Fertilizer

The words organic or natural in regards to fertiliser, means that the product(s) are only minimally processed, and the nutrients remain bound in their natural forms. As opposed to them being extracted and refined.

An organic fertilizer is usually made from plant or animal waste or powdered minerals. Examples include:

  • Bat guano
  • Blood meal
  • Bone meal
  • Chicken excrement 
  • Comfrey
  • Compost
  • Cow manure
  • Greensand
  • Green manures
  • Fish emulsion
  • Horse manure
  • Pig manure
  • Pigeon droppings
  • Rabbit droppings
  • Rock phosphate
  • Sheep or goat droppings
  • Shellfish fertilizer
  • Wormeries

If all of those are organic fertilizer, you’re probably wondering what makes for an inorganic fertilizer. Non-organic fertilizers are synthetic chemicals. Most listed are fairly self-explanatory, for those that are not here is an explanation.

  1. Blood meal – Dried powdered blood collected from cattle slaughterhouses.
  2. Bone meal – Finely ground bone. By-product from animal slaughterhouses.
  3. Greensand – Iron potassium silicate.
  4. Fish emulsion – Partially decomposed blend of finely pulverized fish.
  5. Rock phosphate – Calcium or lime based phosphate rock, typically ground into small pieces.
  6. Shellfish fertilizer – Made from crushed bones and/or shells, from crab or other shellfish.

Organic fertilisers are becoming increasingly popular as we move into an age of conscious living and active organic industries. When growing edible crops or plants and flowers for their oils, people want to know how pure oils are and how organic the produce is.

Advantages of Organic Fertilizer

  • Improve the structure of the soil and increase its ability to hold water and nutrients
  • No risk of toxic buildups of chemicals and salts harmful to plants
  • Renewable, biodegradable, sustainable, and environmentally friendly
  • Slow-release fertilizers – difficult to over fertilize plants

Disadvantages of Organic Fertilizer

  • May not release nutrients as soon as you need them.
  • Microorganisms are required to break down and release nutrients into the soil. effectiveness of organic fertilizer can be limited seasonally
  • Nutrient ratios are often unknown, and the overall percentage is lower than chemical fertilizers. However, some organic products are actually higher in certain nutrients.

Chemical Fertilizers

Chemical fertilizers also known as artificial, inorganic, manufactured or synthetic fertilisers, refer to fertilisers that have been refined to extract nutrients and bind them in specific ratios. Some of the chemicals may be naturally occurring, however, the difference between organic and chemical fertilizers is that the nutrients in chemical fertilizers are refined to their pure state and stripped of substances that control their availability and breakdown. Which would rarely occur in nature. Examples of chemical fertilisers include:

  • Ammonium nitrate 
  • Ammonium phosphate
  • Ammonium sulfate
  • Potassium nitrate
  • Urea

Advantages of Chemical Fertilizer

  • Inexpensive
  • They are highly analyzed to produce the exact ratio of nutrients desired
  • Since nutrients are available to the plants immediately, improvement occurs in days
  • Standardized labeling makes ratios and chemical sources easy to understand

Disadvantages of Chemical Fertilizer

  • Danger of over fertilizing
  • Can contribute to the release of greenhouse gases
  • Long-term use of chemical fertilizer can change the soil pH, upset beneficial microbial ecosystems, encourage pests
  • Made from non-renewable sources some including fossil fuels
  • They grow plants but do little to sustain the soil long-term
  • Repeated applications may cause toxic buildup of arsenic, cadmium, and uranium in the soil. Which can make their way into crops

DIY Fertilizers

It is possible to make your own organic fertilizer by composting or find inexpensive sources, such as local dairy farms that sell composted manure. Commonly used DIY fertilisers include:

  • Banana skin – soak peeled banana skins in water overnight, use water and discard banana skins
  • Black Tea – Make up at least 1 litre of tea organic black tea (without milk), use as feed
  • Compost – Deposit cooking waste and garden waste in a compost bin, apply layer of compost material to desired area of soil
  • Epsom Salt – Dissolve in water and use as a feed
  • Egg Shells – Clean and crush eggshells before adding to soil
  • Vinegar – Mix vinegar with water and use as a feed




Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s