When fertilising you need to remember to use the right mixture, the right quantity and apply it at the right time of the year. A common lawn care mistake is to heavily fertilise in the Spring with the expectation of seeing a plush, green lawn emerge. Most commercial fertilisers contain soluble nitrogen, which in too large a quantity will actually burn your lawn. Too much fertiliser can also encourage thatching and leave your lawn more prone to disease and insect damage.
How Much Should I Use?
The answer here is to follow closely the directions included in your chosen fertiliser. What you want is to encourage the top growth without endangering the root growth or changing the carbohydrate storage ability of your lawn. Fertilisers generally contain 3 major ingredients: Nitrogen (N), Phosphorous (P), and Potassium (K) along with some other minor nutrients.
You will find three numbers on the fertiliser bag which represent the mix of these major ingredients by percentage. The numbers will appear in the N, P, K order. You will also be able to see the guaranteed analysis of the fertiliser on the bag.
Grass needs more Nitrogen than the other nutrients due to its being an essential part of the chlorophyll molecule. This is what causes your lawn to get that deep green colour you want to have. However, Nitrogen will cause top growth at the expense of root growth.
Phosphorus is needed in the energy transfer system of the plant and is needed in a lesser quantity than the other two nutrients in an already established lawn. It is however very essential to a newly planted lawn.
Finally, Potassium helps to make your lawn insect and disease resistant and aids in cell wall development.
Choose a Slow Release Mix
When looking at a fertiliser you should look for a slow-release nitrogen mix. There are two types of nitrogen generally found in most fertilisers, these are organic and inorganic.
Ammonium nitrate and ammonium sulfate are the most commonly used inorganic sources. These are both very soluble which makes them more quickly available to your lawn which will cause a quick growth and greening over a short period. It is however, becoming more common for turf-masters to recommend a slow release organic, nitrogen mix.
The most common forms that these take are sulfur coated urea, I.B.D.U., urea formaldehyde, resin coated urea, methylene urea and natural organics. Using these will produce a good color without sacrificing root growth and because they are slow release, will require less frequent application. The general recommendation of turf experts is to use a fertiliser which has at least half of its nitrogen mix in a slow release form.
An established lawn of either Cool Season or Warm Season grasses will do well with a 3-1-2 or 4-1-2 mix of N, P, K. Among the analysis numbers that fit that ratio you will find: 12-4-8, 15-5-10, 16-4-8, 21-7-14 and 20-5-10.
Read the Label
When determining how much to use, look first at the recommended rates on the bag. You want to apply as little as possible to achieve good growth. Over fertilization will cause excessive leaf growth and weaken your lawn.
To get more advice call our team on (07) 3114 8230. You can also to pop in and order in person at our sales office on 1/243 Bradman Street, Acacia Ridge. The office opens Monday to Friday 7am to 5pm and Saturday 7am to 12pm.
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