Organic vs Inorganic Fertilisers

We are often asked to explain the difference between organic and inorganic fertilisers. Having a background in Nutritional Science, I liken the difference to the consumption of natural food compared to synthetic supplements, which are commonly used these days by many people as a quick fix to get adequate nutrition. Once again the association between human and soil health is apparent.
There are many interesting components to this debate, so we thought it worth putting in a blog. Let’s start with what they are:

Organic fertilisers are made from natural products and deliver a broad array of nutrients in a plant friendly form. Whereas inorganic fertilisers (often called chemical or synthetic fertilisers) are manufactured and concentrated, usually containing a specific set of nutrients in quantifiable amounts.
Let’s break this down further. Plants get most of their energy from sunlight via photosynthesis, but they need other chemical compounds to aid their growth. They get these through their leaves and soil, via their roots. These nutrients are available in an organic and inorganic form. A few key points on both:

Key facts on Organic Fertilisers
  • They break down slowly, therefore release nutrients gradually in the soil
  • They improve soil quality, structure, water holding capacity and enhance microbial life
  • The nutrient content they provide is not precise, but they deliver a wider range of nutrients, including essential macro and micronutrients
  • They are safe for plants, animals and people
  • However, they do have their downsides, they can be bulky to store, require more labour to apply, can be smelly and a often more expensive up front.


Key facts on Inorganic Fertilisers
  • They are easy to store, have a long shelf-life and easy to apply (but overapplication can be harmful to plants and people) and they have been considered cost effective
  • They are precise and you can target specific nutrient groups
  • However, there are significant downsides. Firstly, 60-70% of the nutrients from inorganic fertilisers are not absorbed, rather they wash away into local waterways where they cause widespread environmental damage. Secondly, inorganic fertilisers are harmful to the soil microbiome and do benefit the soil in any way.

In short, inorganic fertilisers feed only the plant (and a few select nutrients at that), whereas organic fertilisers feed the soil, which then feeds the plant and have long lasting benefits on soil health.

Why NKP?
Most inorganic fertilisers on the market contain 3 main elements used by plants, these are nitrogen, potassium and phosphorus, otherwise known as plant macronutrients and displayed as the NPK ratio. They play a vital role in photosynthesis. However, they are not the only nutrients a plant needs to be healthy. Like humans, plants also need trace elements of many other nutrients to thrive. These include micronutrients, such as magnesium, calcium, manganese, iron, sodium and boron, to name a few.
In principle, organic fertilisers are referred to as biostimulants because they stimulate the biological process. In contrast to chemical-based fertilisers, which contain a specific balance of NPK. Organic fertilisers often have lower levels of NPK but contain a collection of other valuable micronutrients, which inorganic chemicals do not.

Plants evolved with nutritional diversity, so a complex menu of nutrients allows the plant to feed efficiently. I once heard the top soil scientist Elaine Ingham explain this well when she said “there are many more letters in the alphabet than just NPK”. Although chemical-based fertilisers will stimulate a response in the plant and cause some growth, this process bypasses vital soil biology and as discussed above, the addition of nutrients without biological balance, will deliver little results and cause more damage in the long term.

What does Bioavailability mean?
Let’s look at the BIOAVAILABILITY of nutrients. Bioavailability relates to the ease in which a plant and its roots can assimilate and utilise a nutrient. When nature breaks down organic material, nutrients are in a form that are readily absorbed by plants. On the other hand, inorganic nutrients (not from a natural source) can be in chemical structure unknown to the plant, which means they cannot interact or utilise it. Money is literally washed away.

This is where it is vital to discuss the benefits of biostimulants like Food2Soil. The unique fermentation process allows for enzymatic hydrolysis, which is a ‘pre-digestion of proteins’, breaking them into smaller amino acids and dramatically increasing the solubility of plant proteins for easy uptake. In short, making them bioavailable to plants, resulting in a healthier plant.

When I started this blog, I told myself I was going to try and be impartial but the more I researched, the more it became clear, organic fertilisers are the way to go! Though sometimes initially more expensive and harder to apply, organic fertilisers are 100 percent worth it in the long run, not only for plant and soil health but also the surrounding ecosystem and wellbeing of the farmers and gardeners.

We have touched on a few key aspects of this topic, if you want to learn more about the benefits of organic fertilisers and plant care, go to Food2Soil or try some Food2Soil in your garden and observe the long lasting benefits.