Organic and Inorganic Fertiliser

Although both organic and inorganic fertiliser are essentially used to promote lawn health and vigour, there are several differences between the two fertilisers. Each type have their own advantages and disadvantages to the lawn and soil etc.

Inorganic fertilisers are man made, chemical based products, while organic fertilisers are derived from natural products or natural substances such as animal manure, blood and bonemeal etc.

For countless years now, there have been debates and differing opinions amongst gardeners over organic and inorganic fertiliser, and which type is more beneficial to the soil and the lawn.

The simple fact is that each type of fertiliser offer their own advantages to the lawn, at the same time they both have their disadvantages too. However it is important to note that the grass plant can’t tell the difference between inorganic and organic fertilisers.

Organic fertiliser

As the name suggests, organic fertilisers are derived from natural or living substances. These substances include dried blood, hoof and horn, farm manure and bone meal. Inorganic fertilisers are made from non-living materials and are chemical based.

The advantages of organic fertilisers

  • Beneficial to the soil and root zone – Organic fertilizers do more than supply the grass plant with vital nutrients, over a period of time they will help improve the soil structure. Organic fertilisers also improve water retention within the soil, this particularly beneficial during periods of drought stress, as it helps the lawn retain a healthy coverage of grass.
  • Grass growth is consistent – Organic feeds create slow, consistent plant growth. This is because they have to be degraded by the soil microbes (micro organisms) prior to them being released and absorbed into the grass plant. This process prevents any unwanted surge or flush of grass growth.
  • Greater longevity – Organic fertilisers have a greater longevity than chemical or inorganic feeds, which all adds up to fewer applications being required to sustain healthy plant growth.
  • The supply of additional trace elements – Organics typically supply additional nutrition to the grass plant in the form of trace elements (most inorganic formulas don’t contain additional trace elements).
  • Safer to apply – How many times have you heard about people damaging their lawns through fertiliser scorch, this is more common when applying inorganic feeds. There are fewer problems with scorching or burning when applying organic feeds.
  • Encourages healthier conditions – Organics encourage healthier soil conditions, thus improving pest and disease resistance, with the end result being less problems in the lawn. Encourages beneficial micro organisms – Organic fertiliser encourages a healthy population of soil micro-organisms which are important for a healthy soil. These soil microbes degrade organic matter, control thatch build up, prevent lawn disease and break down chemicals and toxins in the soil.

Disadvantages of Organic fertilizer

  • Expensive to purchase – One of the drawbacks with organic feeds is the purchase price, they are more expensive than inorganic feeds.
  • Slower response times – Because organic feeds need to be broken down by soil microbes before being available to the grass plant, the time they take longer to work than inorganic feeds. Soil temperate can also be a factor, as soil microbes require warm soils.
  • Application can be difficult – Organic fertilisers take on many forms such as powder and meal, therefore applying them can often be difficult. Solid formulations may lack a consistent particle size, or excess residue is regularly found in liquid feeds and may cause sprayers and applicators to clog up.

Inorganic fertilizer

Inorganic also known as synthetic or chemical fertilizers are man made, they are not derived form natural sources.

Advantages of inorganic fertilizer

  • Availability – As inorganic fertiliser is very common, then availability is not going to be a problem. Many garden centers carry a large stock and a wide selection of brands to suit most budgets and lawn requirements.
  • A wide range nutrient combinations – Inorganic fertilizers are available in wide variety of nutrient combinations, enabling you to find a product suitable for your lawn. There is also a wide range fertilizers for different applications e.g spring and summer feeds (high nitrogen) & autumn and winter feeds (high phosphate & potash).
  • Quick response times – Inorganic fertilizers often ensure quick response times. Results can often be witnessed within a few days of application.
  • Easy to apply – As inorganic fertiliser is available in a variety of formulations, such as liquids, granules, pellets and soluble, application is made easy for the gardener. A range of different spreaders, sprayers and applicators are available for applying these products. Another plus factor is many of these product come with information and advice on spreader settings to ensure accurate calibration and application rates.
  • Cheap to purchase – Inorganic fertilisers are less expensive than their organic counterparts. However it should be noted that some inorganic feeds such as slow and controlled release feeds can prove to be more costly.

Disadvantages of inorganic fertilizer

  • Short life span – Inorganic or synthetic fertilizer have a shorter longevity. This means additional applications have to be applied to maintain the correct level of nutrition for the grass plant.
  • Excess growth following application – Many inorganic fertilisers are fast acting, the downside to this is an unwanted, initial flush of growth.
  • Subject to leaching from the soil – As inorganic feeds are water soluble, it is possible they can be leached through the soil and wasted, (especially following periods of heavy rain fall) before the plant has chance to absorb them.
  • Application problems – The danger with inorganic fertilisers is that if they are not applied correctly (overdosing) they can damage the lawn by scorching the grass and in some cases kill the grass.
  • No real benefits to the soil – Inorganic fertilizers only feed the grass, they will not improve the soil structure and increase micro organism populations, as organics do.

Oliver Thompson
Lawn Care Expert

About Oliver: Oliver Thompson, a seasoned lawn care expert from the Cotswolds with over two decades of experience, invites all enthusiasts to join him in exploring the world of lawns, sharing knowledge, and fostering a vibrant community of lawn enthusiasts. More info

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