When and How Should I Fertilise My Lawn

reading time: 8 min, 32 sec

To fertilise a lawn correctly, you have to do more than just run out, buy some fertiliser, and spread it. Doing the job right involves careful consideration of 4 factors.

Seeding a lawn and mowing it as the grass grows will not be enough to maintain its growth and health. Proper lawn care also requires fertilisation as a part of the ongoing upkeep of your garden & landscaping.

To fertilise a lawn correctly, you have to do more than just run out, buy some fertiliser, and spread it. Doing the job right involves careful consideration of 4 factors: why you should fertilise, what type of fertiliser to use, how to fertilise, and when to do it.

Why Fertilise?

Much like the human body, grass requires certain nutrients in order to grow properly. Those nutrients are nitrogen (N), phosphorus (P), and potassium (K). Nitrogen promotes production of chlorophyll, and chlorophyll is an essential part of photosynthesis, which in turn is vital for healthy blade growth. Phosphorus helps healthy roots and stems to develop, and potassium, used by the human body to help with blood clotting, plays a similar role in lawns by increasing their resistance to drought and disease.

Unfortunately, these nutrients usually do not occur in lawns at natural levels that are sufficient for needed strength and replenishment. Additionally, these nutrients wash away from rain and watering over time.

For these reasons and more, it’s important to fertilise your lawn.

What Type of Fertiliser To Use?

If cost effectiveness is your biggest concern, then you have the option of using a natural fertiliser that is simple to use and which won’t cost you a single dollar extra: all you have to do is leave the grass clippings on your lawn after you cut it. However, there are potential drawbacks to that. The principal one is that if you don’t mow often enough, you’re prone to leaving large clumps on the lawn, which can be ugly, and can also kill the grass beneath, defeating the purpose. In the end, that will cost you more time and money because you will have to reseed and you will have to combat weed growth that loves to take over dead, bare patches.

Using a commercial fertiliser is what we recommend. Still, it’s not so simple. At the store, you will find many different options, and the differences include not only the brand names but also the forms of application and the concentrations of the nutrients your lawn needs.

Most grass needs a fertiliser with a high level of nitrogen. On a bag or package, you’re going to find what lawn scientists and professionals call the N-P-K ratio. This ratio shows the relative percentages of each nutrient. If, for example, the ratio is 25-5-10, the product is 25% nitrogen, 5% phosphorus, and 10% potassium.

Knowing what type of grass you have and what its needs are will be critical for selecting the right combination to get. Understandably, not a whole lot of people know these things. Instead of guessing or spending valuable time doing research, it might be a good idea to consult a lawn-care professional about those considerations.

How to Fertilise?

As you choose the right fertiliser mix, you also have to decide how you want to apply it. You’ll have a choice between quick-release formulas and slow-release ones. What are they? Which one is better?

Quick-release fertilisers come in liquid form as sprays. The pros are that they’re usually cheaper and they work faster; most of the time, you’ll see results within a few weeks. On the down side, they don’t last as long as slow-release fertilisers do. This means they have to be reapplied more often, and when they are overapplied, they can “burn” the lawn and damage or kill grass.

Slow-release fertilisers, on the other hand, come in a granular form. To apply them, you use adjustable spreaders to control how much you put down at a time. You also need to water them in for them to work and so they won’t wash away if it rains. Their 2 main drawbacks are that they work more slowly and that they are more expensive. Compared to quick-release fertilisers, though, they last longer, so they don’t need to be reapplied as often. Also, they are harder to misuse (and therefore much less likely to cause damage to your lawn).

Whichever type you use, it’s also critical, and actually a matter of personal and public health, to make sure the fertiliser does not get into our waterways and pollute them. Immediately clean up excess amounts and spills, especially when they occur on surfaces like driveways and sidewalks where they could be washed away into storm drains and other runoff channels. Take care not to overwater, which can result in runoff. If you are using sprays, don’t apply them on windy days.

When To Fertilise?

Timing is a critical component in so much of lawn care, and fertilisation is no exception.

The best times for fertilisation depend on climate and soil type. In sandy areas like Perth and the western seaboard, fertilisation can be necessary up to 5 or 6 times per year. Here in the Sydney region, we recommend at least three treatments a year: in early spring, summer, and autumn.

With a spring treatment, new growth gets off to a great start. The heat of summer is tough for a lawn to endure, especially for new grass, and a summer treatment helps maintain growth through the heat and into autumn. In advance of winter, an autumn treatment protects the lawn and also sets the stage to ensure a strong, quick start the following spring.

What Are the Benefits of Fertilisation?

The valuable benefits from fertilising a lawn include the following:

  • Grass shows thicker, with more uniform growth.
  • The lawn has a higher resistance to disease.
  • Because thick, healthy grass is harder for pests to thrive in, you’ll see fewer of them.
  • Likewise, thick grass with strong roots doesn’t leave as many opportunities for weeds to grow, and weed control is easier.
  • Thick grass and strong root systems also prevent the soil from washing off, which further enhances the growth and health of the lawn.

    Go with the Garden Men To Save Time, Hassle, and Money!

    As we mentioned and as you can probably see by now, fertilisation is a little more complicated than just going out a few times and spreading fertiliser. It works best at particular times and in the proper concentrations and applications, yes, but there are other considerations, too.

One of the foremost concerns has to do with using a pre-emergent or a post-emergent weed-killer treatment. Using fertilisers and herbicides at the same time can mean ineffective results from the fertilisers and can inhibit grass growth or outright kill your lawn.

While it is possible to do both at once, it’s a task best left to the experts, as is the decision about exactly what times of year to fertilise.

Plus, do you really have the time to devote to doing all of this properly? If you do, are there other things you’d rather be using it for? When you factor in the value of your time and the money you spend on materials, using a professional can end up being less expensive - and that’s not even considering if you do some damage!

The Garden Men is a leading landscaping and lawn maintenance company, beautifying and protecting residential and commercial properties around the Sydney region for over 20 years. Our expert property and garden maintenance will add to your home’s value and appeal while keeping it looking great. If you’re ready for the best lawn care in the Sydney area, contact us today!

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