How to Use Sudden Impact for Lawns

There are a multitude of lawn fertilisers that you can choose from and the selection can often be overwhelming. The most important thing to remember is that you want a fertiliser that is high in nitrogen because that’s what is going to keep your grass nice and green and produce lots of fresh new growth.

Of course, grass also needs nutrients other than nitrogen, such as phosphorus, potassium, calcium, iron, magnesium, and sulphur. These all promote healthy root growth and tough grass that is less susceptible to pests and diseases. 

One of the more popular lawn fertilisers in Australia is Sudden Impact for Lawns, made by local company Neutrog. It contains most essential nutrients and is high in nitrogen. It’s also in granular form which makes it very easy to apply to your lawn.

What type of fertiliser is Sudden Impact?

Sudden Impact is a granular fertiliser that you spread over the lawn either by scattering by hand or by using a broadcast fertiliser spreader.

fertilizer hand spreader | Lawn care

The fertiliser is organic based and has been boosted with a variety of water-soluble nutrients as well as living bacteria and microbes.

The nutrient breakdown of the product is as follows:

  • Nitrogen 11.64%
  • Phosphorus   1.0%
  • Potassium   6.28%
  • Sulphur 15.90%
  • Calcium   1.47%
  • Iron   1.29%
  • Magnesium   0.45%

Essentially, this gives you an N:P:K of 12:1:6 which is ideal for good lawn growth. The product also contains trace amounts of other nutrients such as zinc, manganese, copper, molybdenum, and boron. 

What types of turf can you use it on?

Sudden Impact can be used on all types of turf including Buffalo grass. It’s suitable for both new and established lawns.

How to use Sudden Impact for Lawns

Lawn Fertilizer 1 | Lawn care

As Sudden Impact is a granular fertiliser, it needs to be broadcast over the entire lawn area. This should be done throughout spring, summer, and autumn.

Most lawns these days consist of warm-season grasses and this means that they shouldn’t be fertilised in winter because the grass is not actively growing at this time.

Here’s a breakdown of the suggested application rates:

New Lawns

Apply 100gm of Sudden Impact per square metre of lawn. Ideally, you want to incorporate this into the top 10 cm of the soil before you seed or lay your turf. This gives the new grass plenty of nutrients to start growing strongly.

Established Lawns

Apply 50gm of Sudden Impact per square metre of lawn. Make sure that you water the lawn well after applying the fertiliser. This will release the water-soluble nutrients that are contained within the granules while the slow-release natural nutrients will be released as the grass needs them over time.

It’s advised that you apply Sudden Impact once every six to eight weeks over the active growing season in order to promote a lovely lush, green lawn.

Expert tip: “Make sure that the soil is moist before applying. Apply just after it has rained or after you’ve watered the lawn. Then, water again after application”. – Graham Ross from Better Homes & Gardens

How does Sudden Impact fertiliser work?

Sudden Impact works in two prime ways to provide nutrition to your lawn. When you first apply the product to your grass and water it in, the water-soluble parts of the fertiliser will be released and give your lawn an instant boost.

inspecting lawn | Lawn care

Then, because there are also slow-release elements to the fertiliser thanks to its organic base, these nutrients will be released slowly over a period of around 6 to 8 weeks as the roots of the grass need them.

This is the perfect way to keep your lawn nice and healthy because the roots have constant access to nutrients to keep the grass growing nice and strong.

Pros and Cons of Sudden Impact fertiliser

As with any garden product, there are likely to be pros and cons and the same is true for Sudden Impact for Lawns.


  • Contains a perfectly adequate amount of nutrients
  • Is mostly organic but chemically boosted
  • The granules make it easy to apply
  • Will feed your lawn instantly and then feed the roots when needed
  • Promotes healthy grass and healthy soil


  • It’s quite expensive compared to other lawn fertilisers (around $5 per kg)

Best Sudden Impact alternatives

If Sudden Impact for Lawns is a little too expensive to fit into your budget, there are a few lower-priced alternatives that you might like to consider. These include:

  • Eco88s (similar nutritional content but half the price)
  • Yates Dynamic Lifter Concentrated Lawn Food (around $4 per kg)
  • Yates Dynamic Lifter Organic Lawn Food (around $3.80 per kg)

It’s no secret that I’m a big fan of Dynamic Lifter and have been using it in my garden for many, many years. But, for those that have never used it before, be aware that it does have a slight manure odour. However, it’s not only good for the grass but helps to keep the soil healthy too.

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Annette Hird

Annette Hird is a gardening expert with many years of experience in a range of gardening related positions. She has an Associate Diploma of Applied Science in Horticulture and has worked in a variety of production nurseries, primarily as a propagator. She has also been responsible for a large homestead garden that included lawn care, fruit trees, roses and many other ornamental plants. More recently, Annette has concentrated on improving the garden landscape of the homes that she has lived in and focused a lot of energy on growing edible plants as well. She now enjoys sharing her experience and knowledge with others by writing articles about all facets of gardening and growing plants.


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