Lawn fertilizer for a healthier lawn
Like all living things the grass requires certain amount of feed (nutrients) to remain in a
If the lawn is lacking in any nutrients it's health will suffer and it becomes susceptible to
many types of lawn related problems, pests & diseases. The same can also be
said of a lawn that contains too many nutrients, so it is important to get the balance right with
the correct lawn feed & fertiliser program.
Nutrients used in lawn fertilizer
There are 3 key nutrients that are used in lawn fertilizer programs. These nutrients are
Nitrogen, Phosphorous (Phosphate) and Potassium
- Nitrogen (N) - This is the most important nutrient in any lawn fertilizer.
The role of nitrogen is too produce strong consistent growth. It gives the grass it's dark
green colour during the summer months.
Nitrogen is used in many lawn care products such as lawn sand and weed and feed products. It
can also be used a straight (on it's own) fertilizer but is more commonly used with phosphate
(P) and potassium (K) as a complete compound fertilizer.
Nitrogen is used in spring and summer lawn feed and fertilizer programs. It should not be
applied in large quantities later than mid August and certainly not during the autumn and
winter months. Applying Nitrogen at these times of the year can cause major
disease problems during the autumn and winter. You may need to apply nitrogen
more than once a year (every 6-8 weeks) as it is easily leached through the soil.
- Phosphorous (P) - Phosphorous is important for maintaining a deep healthy
root system. This results in earlier growth during the spring, also more nutrients and water
can be tapped into during periods of drought and stress due to the increased rooting. Unlike
nitrogen it can be applied any time of the year but one application per season is usually
- Potassium (K) - Although Potassium is not as important as nitrogen and
phosphate it is still required or maintain a healthy lawn. Potassium hardens the turf, helping
with disease & drought resistance. It can also be applied at any time of the year, again
one application per annum is usually enough.
What to use and when to apply a lawn fertilizer
There are two main types of fertiliser, they are spring & summer and
autumn & winter fertilizers. The main difference in these fertilizers apart
from the timing of application is the amount of nitrogen contained in each. Spring & summer
feeds contain a large percentage of nitrogen while autumn & winter feeds contain very little
- Spring & summer fertilizer - A spring/summer feed contains a high
percentage of Nitrogen and may also include some additional Phosphate & Potash. This
fertilizer can also be part of a weed, feed and moss control formulation.
The spring & summer fertilizer is always the first to be applied, usually from late March
onwards when the temperatures have started to rise.
A further application/s may be necessary during the growing season depending on the fertilizer
type, climate, soil type etc. However it is important not to apply a spring & summer
fertilizer to late in the season (after August). This can lead to disease
problems (due to the high nitrogen content) during the autumn.
- Autumn & winter fertilizer - Autumn/winter feeds are usually applied
once annually, September/October being the optimum time for application.
An autumn/winter fertilizer will contain a high percentage of Phosphate & Potash and small
amount of Nitrogen.
An autumn/winter feed may also contain some sulphate of iron (iron sulphate). This will help
harden the turf against disease, discourage worms and moss. Iron sulphate also helps cosmetically by turning the
lawn a deep green colour without stimulating growth.
Types of lawn fertilizer
There are two types of lawn fertilizer, liquid and granular, both have their advantages and
- Liquid fertilizer - These type of fertilizers are have a quick response
with a rapid green-up. However the longevity of liquid fertilizers are generally quite short,
therefore re-application is necessary quite often.
Liquid fertilizers are generally diluted with water when applied, by means of a
hose-end applicator, watering can or a hand
held or knapsack sprayer.
- Granular fertilizer - Granulars are longer lasting than liquids therefore
require fewer applications. They can be slow release (lasts anywhere from 8-12
weeks) or conventional release (lasts about 4-6 weeks).
Granulars can be applied by hand but for the best results a hand or push spreader can be used.
It is important that granular fertilizers are watered in after application to prevent scorching
the grass or worse.