Fertilisers - Synthetic vs Organic

Preparing and enriching your soil for growing your own vegetables is very important as most vegetables are short-lived annuals and need a lot of nutrients so they can grow and develop quickly.

Fertilisers come in two forms:

• synthetic (man-made)
• organic (naturally occurring)

Synthetic fertilisers were developed during the Industrial Revolution, whereas organic fertilisers have fed the soil since time began. Synthetic fertilisers are produced chemically but, just to confuse things, they can be called “organic” if they are made with natural ingredients.

Organic fertilisers are made from any material that contains carbon and once was alive – for example, leaves, animal skeletons and manure.

Synthetic fertilisers are made to a recipe and provide a fast release of essential nutrients. Often, the mixture of elements is designed for specific plant species. For example, citrus fertiliser is chemically balanced to provide citrus trees with everything they need. They don’t rely on the micro-organisms to make the nutrients available to the roots and the nutrients dissolve quickly, allowing the plant to absorb them immediately.

The trouble with synthetic fertilisers is they only provide nutrients that run out quickly and do not do anything to improve the structure of the soil. Organic fertilisers, on the other hand, provide not only nutrients but also food for the micro-organisms and they release the nutrients slowly, which prevents root burn and, most importantly, helps improve soil structure.

If your soil is sandy, organic matter helps to bind the particles together, improving nutrient and water-holding capacity. If your soil is clay, organic matter helps separate the particles and improves the drainage, oxygen level and nutrient availability.

Organic fertilisers come in several different forms. They can be pellets such as chicken manure; they can be solid/powder, such as blood and bone; or they can be liquid, which you add a little of to your watering can. If liquid is poured over the leaves, they are immediately able to absorb the nutrients (though in winter this process is slower)

It’s important to read the packet/bottle labelling to see if all 13 nutrients are included or just one or two. Blood and bone, for example has only nitrogen and phosphorus, so is said to be incomplete.

As complete organic fertiliser contains all the nutrients, including trace elements such as boron, calcium, zinc, molybdenum, sulphur ect.

The other positive aspect of organic fertilisers is they help to increase the biodiversity of your soil; the more micro-organisms in your soil, the healthier it will be. Micro-organisms include bacteria, viruses and fungi as well as larger creatures such as worms and beetles.

These organisms are all involved in the decomposition process. For example, some fungi are able to break down organic matter into tiny components and then bacteria transform the nutrients into forms that roots can absorb. Some fungi and bacteria protect the plants’ roots from being attached.

So you can see that these types of natural fertilisers give you much more than just chemicals – they are involved in the chain of life.

Extract from an article written in Good Gardening Margazine