Fertilisers

A fertiliser provides one or more essential plant nutrients to aid growth and health, and can be applied to the turf surface or rootzone. The main fertiliser nutrients applied to turf are nitrogen, phosphorus and potassium, followed by iron and occasionally magnesium:

Nitrogen (symbol N) for leaf development and vivid green color.

Phosphorous (symbol P) for root growth.

Potassium (symbol K) (or potash) for root development and disease resistance.

You can tell what is in a fertiliser by the three numbers on the packaging. The numbers denote the percentage of the primary nutrients’ make-up by weight, as above.

Besides ensuring that adequate supplies of nutrients are available to the grass plant to aid it in making healthy and strong growth, there are other particularly important reasons why sufficient nutrients need to be applied:

1. The density of the sward can be increased.

2. Desirable grass species can be encouraged, while less desirable grass species and weeds can be discouraged. This can be achieved by using different types of fertiliser which have varying effects on soil pH.

3. The sward’s ability to withstand wear and recover quicker from use is enhanced.

4. The colour and visual appearance of the sward can be improved.

5. A more uniform grass sward, which is without the presence of weeds, can be achieved.

6. Root growth can be improved.

7. A sward which has an improved ability to withstand the vigours of drought, cold and harsh weather can be acheived.

8. A more disease resistant sward is also produced.

9. To provide a sward which produces a good playing surface.

Fertiliser is available in both liquid and granular form. Liquid fertilisers are fast-acting and as they are quickly absorbed, they will need to be applied every two-three weeks. Most are supplied as concentrates then mixed with water prior to application.

Granular fertilisers are applied dry and need to be watered in. They are easier to control because you can actually see how much fertiliser you are using and where it is being dispersed, and they are available as quick or slow-release formulations.

Quick or slow release?

Quick-release fertilisers typically last for around three to four weeks, however factors such as temperature and rainfall can affect this.

There are two main types of slow-release fertilisers:

• Sulphur coated, which lasts for about eight weeks (depending on weather conditions)

• Polymer coated, lasting about 12 weeks (depending on weather conditions).

We surveyed our readers to find out which fertilisers they use and why, and the results are as follows: