Putting the “O” back in optimal growth

Building an eco-house
February 1, 2018
Homegrown: sustainability starts at home.
February 14, 2018

We have all heard of organics, but what is it and what is the natural function of soil? Are chemical fertilizers the devil and is organics going to save the world?

The modern farming revolution was built on NPK – the three most important components for plant growth. This golden ratio has become synonymous with chemical fertilisation. These varying ratios for different varieties of plants and trees, allowed commercial agriculture to push production and yields. But what is NPK and how is chemical fertilisation different to growing organic?

The modern food revolution focused on chemicals and their NPK values and it was the cheapness of chemicals that made them the agricultural wonder drug of an earlier era. The three numbers represent the values of three macro-nutrients used by plants, nitrogen (N), phosphorus (P) and potassium (K) or NPK for short. The height of the number represents the quantity of one in relation to the others, for example, 20:5:5 would have four times more nitrogen in it than phosphorus and potassium.

Nitrogen – nitrogen in largely responsible for leaf development.

Phosphorous –  root growth, flower, seed and fruit development.

Potassium – promotes strong stem growth and supports the overall functions of the plant.

NPK is simply the ratio of nitrogen, phosphorus and potassium given to plants; this can be as organic or inorganic forms. Organic can be in the form of dead plant waste (or what we commonly call compost) and animal waste (manures or organic material that has passed through the gut of an animal). Manures’ value is its concentration of NPK.

Inorganic fertilisation is the same NPK mineral nutrients that has been mined, refined and packaged as a bag of chemical fertiliser found in a store. The levels are often very high and the chemicals strong, as they are highly concentrated.

The ratio NPK you see on bags indicates what is provided to the plant, not what the plant is able to take up. It is important not to misunderstand the ratio and amount given to plants with the amount made available to plants, a mistake which is common in modern agriculture. The chemical revolution was built on organic soils, because that was the technique preceding chemicals. The results were initially fantastic, as it is the organic function of soil that supports the way chemicals feed plants.

There are numerous factors that determine what a plant is able to absorb, effectively eat for its dinner and it is true that NPK is the basic building blocks of healthy growth. Chemical fertilisers are not the devil as such, their danger lies in the form they come in, their strength and the soils ability to process them. But what’s that? The soils ability to process them?

Microbes are a plant’s partner in its relationship with absorbing nutrients and fertilisers in its immediate environment. It is microbial action that converts chemical formats, that may sometimes be poisonous, into the formats plants require to feast on. The nitrogen cycle is most commonly understood: through microbial action, a poison like ammonia can be transformed into nitrates, a plant food. Plant roots have special relationships with microflora and micro fungi in soils. The pH in soil is incredibly important in determining if a plant can take up nutrients or not. There are many more factors that come into play – other micro and macro nutrients, minerals, hormones and enzymes.

Organics is nature’s way of keeping everything in balance. Everything from the amount of water the plant has to drink, to what it eats, to how all of this keeps it healthy, resistant to disease and able to chase off pests.

Soil and its relationship with plants is an organic one. The split between “organic farming” and farming with chemicals is simply that modern agriculture has forgotten that the soil we farm in is organic soil.  Time has shown that forgetting to support soil’s organic function and to only focus on chemicals, slowly leads to the physical and biological degradation of that soil. If  it degrades over time, there is nothing to support chemicals in the soil and chemical availability is hindered – leading to increased application and a downward spiral.

So, do we need to throw out our chemicals? The answer to this is no. Providing NPK for your plants can be done organically or inorganically. The use of organic sources of NPK is as old as time itself. Responsible use of chemicals is key. While keeping soil organically healthy, chemicals will still play their part in modern agriculture.

Think of bacteria and the organic function of soil as a factory. Bags arrived with square pegs, but those pegs need to be put through round holes. It is the little factory that hammers those square pegs round so that they can fit through those holes. If the NPK were a box of apples, pears and bananas delivered to your door, it would be the healthy function of organic soil that ensures you sit down to a healthy breakfast, lunch and supper daily; one apple, one pear and one banana, just what you need.

What is the answer to our very first question, “is growing organically going to save the planet?”

The answer to a large degree, is irrelevant. The fundamental function of soil is organic, it has been with us since the beginning of time and it will continue to do its thing with or without us. The evolution of man has been based on our ability to play to our strengths and make use of the opportunities afforded to us. Nature is here to support us, she has put in place highly optimised systems to do just that. We can work with her if we want, it is simply up to us.


Nicholas is a farmer and vermiculture specialist with a passion for building healthy soil and encouraging people to grow with optimal effect.

If you want to hear more about Nicholas and his thoughts on healthy sustainable agriculture, be sure to catch his talk at Spark Festival 2018, from 2 – 4 March.
Or take a look at their webpage optigrowgroup.com

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