First lets define what is a chemical fertiliser? It is a fertiliser manufactured using synthetic materials with additives to bind the nutrients in a small granular form.

What is an organic fertiliser, it's sold either in pellet, or powder form, and derived from chicken excretion, cattle droppings and many other living animals by products.

Chemical fertilisers are probably the most complex of fertilisers, due to the amount of differing types and mixtures. The main ingredients, or nutrients, are the elements nitrogen, phosphate and potassium, however micro elements and pesticides are sometimes added. Deciding which to use can be a bit of a “head scratch” if you have no idea what the soil requires. Green keepers of golf courses will never guess as to the requirements of their grasses, but will sample the soils, have them analysed and from the results, decide on the grasses requirements.

There are fertilisers available that are slow release, heat sensitive, and moisture sensitive, all requiring certain conditions before nutrient release takes effect. All very technical, and not a subject that I intend to cover, let the manufacturers sell their own products. The bags, marked with exactly what is the mix, e.g. (2.3.2.) (3.1.5.) (L.A.N) the most popular used by gardeners. These may contain a percentage on the bag i.e. 23%, 40% etc. and this is an indication as to the strength of the elements within the bag.

Chemical fertilisers can also come in liquid form, and these are normally used by specialist for specific purposes, e.g. liquid iron, used by Greenkeepers to quickly turn golf greens surfaces greener. But the same combinations of ingredients can be applied to the plants as foliage feed, again normally applied by specialists. Should these be used by garden enthusiast? Why not, as long as the adage of “less, more often” rather than “more, less often” is followed.

Chemical fertilisers, when incorrectly applied can cause a lot of damage to the garden, over application can lead to the burning of the plants, pH levels can be affected due to the chemicals used to coagulate the products. A chemical fertiliser can contain a high acid level, that once in the soils can almost totally destroy the micro organism within the soil structure. This should be avoided because of the advantages of having a good, rich ecosystem within the root zone. However the advantages of having an immediate availability, of the plants main nutritional requirements, may supersede the disadvantages if high production levels are sought.

Organic fertilisers are less complex, and on occasions it is difficult to exactly determine what nutrients strength is contained in the bag. However, due to the use of organic material to produce the fertiliser, it is probably more advantageous to the gardener, because this type of fertiliser is further broken down by the micro organisms in the soil and only then releases the nutrients to the plant. One can see an immediate disadvantage for the use of this type, it is a slow releasing fertiliser. But the advantages are many, there is an automatic build up of micro organisms, it is almost impossible to burn a plant, (I have over applied on grass by 200%, and experienced no sign of plant distress) and the chances of an environmental disaster, nil.

Organic fertiliser should be worked into the soils early in the season and given time for functioning within the root zone. The health of the plant is improved, and pest control appears far less of a problem. Healthy plants are not attacked by pests, I again use one of my favourite analogies, “a healthy human body will resists disease far better than an unhealthy one” this also applies to plants. Disease and pests, attack week plants, healthy plants can fight off these attacks. A healthy antelope is able, (if not surprised) to escape the claws of the lion, but the sick, lame and injured are easy prey.

Organic or chemical, which is best? In my opinion, the use of organics, whether in dry form or as a foliage feed, is better utilised by a gardener. Leave the chemical fertilisers to the farmers and groundsmen of sporting facilities, the accuracy of the application quantities require specialised equipment, and the “hit and miss” applications in gardens are more suited to organics.