Lawn fertiliser, feeding & nutrition

A verdant, well-manicured lawn is often the cornerstone of a beautiful garden. However, achieving and maintaining this lushness requires more than just regular watering and mowing. It’s here that lawn fertiliser comes into play. As we navigate the world of lawn care, understanding the role of fertilisers and how to use them correctly is essential. So, let’s embark on a journey to unlock the secrets of lawn fertilisers.

What is Lawn Fertiliser?

At its core, lawn fertiliser is a compound, either organic or synthetic, that supplies essential nutrients to your grass. Plants require a wide range of nutrients for healthy growth, and while some of these are naturally found in the soil, others deplete over time or might be missing altogether. Fertilisers help bridge this nutritional gap, ensuring that your lawn remains lush, dense, and green.

There are many nutrients that the grass plant requires, but there are 3 key nutrients that most lawn and turf areas require to maintain optimum health and vigour. If any of these 3 nutrients are deficient then the health of the lawn is likely to suffer somewhat.

The 3 nutrients that a lawn fertiliser should contain are Nitrogen (N), Phosphates (P) and Potash (K), all three being essential for a healthy and vigorous lawn. It is these nutrients that we shall cover on this page. We shall look at the role and importance to the grass plant that these nutrients provide.

The primary nutrients found in fertilisers are:

  • Nitrogen (N): Nitrogen is important for plant growth and it gives the leaf its deep green colour. It is the most important of the 3 main nutrients in a lawn feed, as it is readily used up by the plant, and is leached through the soil more than the others. Used in the spring when the temperature rises, it helps to kick-start and maintain growth going into summer. It should not be used in large quantities during the autumn and winter months as it could lead to a fungal disease attack, particularly fusarium patch disease. Fusarium can be quite severe in the winter so it is essential not to apply large quantities of nitrogen later than late August / early September.
  • Phosphates (P): The main reason for applying phosphates is to produce a healthy and vigorous root system. This encourages earlier growth in the spring time resulting in a healthier lawn during the summer months. Although it is more readily available than nitrogen within the root zone it may still be beneficial to apply some phosphates at least once a season.
  • Potash (K): The main role of potash is to harden the plant, helps make the plant less susceptible to drought and helps with plant metabolism. Potash is important during the autumn and winter months as it helps with disease resistance.

Which Lawn Fertiliser is Best for My Garden?

The ‘best’ fertiliser isn’t a one-size-fits-all answer. It largely depends on your lawn’s specific needs, which can vary based on soil type, grass variety, and local climate conditions. Here’s a simplified guide to help you make an informed decision:

  1. Soil Testing: Before you select a fertiliser, it’s wise to test your soil. This will provide information on its pH level and nutrient content, allowing you to choose a product tailored to your lawn’s needs.
  2. Slow vs. Quick Release:
    • Slow-release fertilisers break down over time, providing nutrients steadily and requiring fewer applications. They’re ideal for maintaining established lawns.
    • Quick-release fertilisers give an instant nutrient boost but last a shorter duration. They’re best for lawns that need a quick pick-me-up.
  3. Organic vs. Synthetic:
    • Organic fertilisers are derived from plant and animal residues. They release nutrients slowly and improve soil structure. Examples include seaweed extracts and bone meal.
    • Synthetic fertilisers are manufactured and can provide precise nutrient ratios. They’re great for targeted applications, such as addressing a nitrogen deficiency.
  4. Specialty Fertilisers: There are products tailored for specific needs, like starter fertilisers for new lawns or winterisers that prepare your lawn for colder months.
  5. Nutrient Ratios: Check the numbers on the fertiliser bag, usually written as N-P-K. A fertiliser with 10-10-10 means it contains 10% nitrogen, 10% phosphorus, and 10% potassium. Depending on your soil test results, you’ll choose a product with the right nutrient balance.

Using Lawn Fertiliser Effectively:

Now that you’ve chosen your fertiliser, here are steps to ensure optimal results:

  1. Follow Instructions: This can’t be emphasised enough. Over-fertilising can damage your lawn, while under-fertilising might not yield the desired results.
  2. Even Distribution: Use a spreader to ensure uniform distribution. This prevents ‘burning’ patches on your lawn due to excessive fertiliser.
  3. Watering After Application: This helps in absorbing the fertiliser. If you’re using a granular product, watering ensures the granules reach the soil.
  4. Safety: Keep fertilisers away from water sources to prevent contamination. If you have pets or children, ensure the product is safe for them or restrict their access to the lawn for the recommended period.

How to apply Lawn Fertiliser?

Applying a fertiliser to the lawn is one of the most important tasks in lawn care. A balanced feed program helps promote healthy turf that is able to withstand most typical lawn care problems.

Lawn fertiliser

A spin fertiliser spreader is the perfect implement for applying all types of granular fertiliser to the lawn. They help make the job quick and easy and the fertiliser is applied evenly over the lawn.

The results of a healthy lawn include good grass colour, increased wear tolerance, good disease resistance, excellent weed suppression and good root development resulting in improved drought resistance.

What to use & when to apply a feed to the lawn

The first fertiliser application of the year should be at the start of spring. This is when the temperatures are starting to rise and the grass is starting to finally show some growth, after the cold winter months. This application should be a nitrogen based fertiliser with additional phosphates and potash.

There are different types of lawn feed on the market, for example: you may want to use a slow release fertiliser. These are generally more expensive than conventional fertilisers, the advantages being that you get slower, more consistent growth with greater longevity.

Alternatively you can use a conventional fertiliser where you will tend to get very quick growth and less longevity. Depending on the fertiliser used in spring a further application may be necessary during the summer months.

You can also choose bewteen organic and inorganic feeds for your lawn, both have their advantages and disadvantages, which are discussed on the organic and inoganic fertiliser page.

Heading into the winter months your fertiliser program should be Phosphate and Potash based to harden up the plant for winter. Very little nitrogen should be applied during this period as this can lead to disease problems.

It is important to choose the correct weather conditions for your application. If you are applying a granular feed it will be best applied during periods of showery weather. Make sure that the foliage is dry when you apply your feed. If no rain falls after the application, make sure it is watered in thoroughly to prevent the lawn scorching.

Liquid feeds may need a different approach depending on whether you are using a foliar feed or root feed. Whatever you choose it is important to follow the manufacturers instructions.

Methods of lawn fertiliser application

Which ever method you use it is important to try and get an even distribution on the lawn to prevent scorched or missed areas. The main application methods are as follows:

  • Hand Application: This is probably the most commonly used method of fertiliser application, however the main problem with this method is uneven application. The correct way to apply, is to apply half the rate going up and down the lawn. Apply half the rate again using the same method by going cross ways, 90 degrees from the first pass.
  • Hand Held Applicator: There are two types of hand applicator the first has a spreader nozzle that fixes on to the container holding the fertiliser. The second type is a hopper that is hand held and a handle is then turned and the fertiliser is distributed via a spinner onto the lawn.
  • Liquid Application: Some fertilisers are soluble, or in a liquid form therefore require a liquid applicator. There are many types available including a watering can, knapsack sprayer or a hose end applicator.
  • Wheeled Distribution: There are two types of wheeled applicators (see pictures below). A spinner type spreader which as it’s name suggests spins out the fertiliser and is ideal for large areas as it covers a large area quickly. The other type is a drop spreader which is slower than a spinner type, but when used correctly is a very accurate method of application.
Lawn fertiliser spreader
A drop fertiliser spreader
Lawn fertiliser spreader
A spin fertiliser spreader
John Storm

Oliver Thompson
Lawn Care Expert

About Oliver: Oliver Thompson, a seasoned lawn care expert from the Cotswolds with over two decades of experience, invites all enthusiasts to join him in exploring the world of lawns, sharing knowledge, and fostering a vibrant community of lawn enthusiasts. More info

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