Nutrients can be also washed through the soil (leaching) as well as being removed through grass clippings each time we mow the lawn. Therefore a lawn will require additional nutrition to be added periodically throughout the year.
A balanced lawn fertiliser program will ensure that your lawn remains in tip top condition. A healthy lawn will suppress lawn weeds and disease and will also be better able to withstand adverse conditions such as drought, wet and frosty conditions.
A balanced lawn fertiliser will include 3 key nutrients, these are nitrogen, phosphorous and potassium. Each of the nutrients plays a key role in a healthy grass plant, if any are deficient the health of the lawn will suffer.
We will take a closer look at the role of each of these nutrients has on the lawn.
Nitrogen - This is the most important nutrient used on lawns and turf. The main role of
nitrogen is to create plant growth and it gives the turf it's rich green colour. Nitrogen is applied to the
lawn during the growing season as part of a spring / summer fertiliser (April - August). It is not used in
large quantities during the autumn and winter as it can cause problems with lawn & turf diseases such
Phosphorous - Phosphorous is important for a healthy root system on the lawn. It can be
applied any time of the year but is predominantly used late in the growing season in an autumn / winter
Potassium - Potassium is responsible for hardening up the grass plant and will help
discourage disease and withstand drought conditions better. Again it can be applied any time of the year,
with the spring and autumn being preferable times for application. AS we previously touched upon there are
two different types of fertilizer formulations used on lawns, these are spring / summer and autumn / winter
Spring & summer fertiliser. This lawn fertiliser is used at the beginning and during the growing season to encourage and maintain good, consistent growth when it is most needed. This helps maintain a good, thick, healthy lawn which will help suppress weeds and help the lawn withstand drought.
A spring/summer feed will contain a high percentage of nitrogen with smaller amounts of phosphorous and potassium. It may also contain some iron sulphate for moss control and a selective weed killer for weed control.
Autumn & winter fertiliser. This fertiliser is applied late in the growing season during the autumn. An autumn/winter feed contains a high percentage of phosphorous and potassium with very little nitrogen. The purpose of this lawn fertiliser is to keep the lawn healthy during the winter and into the following spring.
Slow release lawn fertiliser
Lawn fertilisers are available in both conventional form or slow release form. There are advantages with slow release fertilisers and lawn feeds.
- Longevity - Slow release fertilisers last longer, therefore fewer applications are necessary over the course of the year.
- Consistent growth - Grass growth is more consistent with a slow release fertiliser, there is no sudden flush in growth. A conventional lawn fertiliser tends to encourage a quick growth spurt then tails off before another feed is needed.
- Lower scorch risk - When a slow release is applied the risk of scorching the grass is reduced.
The main disadvantage with a slow release fertilizer is they are more expensive than conventional lawn fertilisers.
Granular or liquid lawn fertiliser
Lawn fertiliser is available in both granular or liquid formulations. With each type of fertiliser comes advantages and disadvantages.
Granular fertilisers - Granular fertilisers can be applied by hand or by spreader.
Although initial response after application maybe slower than a liquid, it will last longer requiring fewer
Granular fertilisers also require watering in thoroughly after application to eliminate any scorch damage to the turf or lawn.
Liquid fertilisers - Liquid feeds can be applied by a watering can or a suitable
sprayer such as a knapsack. Liquid feeds work quicker than granulars but they do not last as long.
Liquids are generally safer to apply as there is less risk of scorch than with a granular feed.