5 steps for fertilising a lawn – discover when to do it, which products to use and how to get the best results

Knowing how to fertilise a lawn correctly is often the difference between a lush, thriving lawn and a patchy brown one. A good feed will make the grass greener and thicker, while at the same time toughening up your lawn so that it can compete against both weeds and heavy wear and tear.

Keeping your lawn looking its best takes time and effort, especially during the spring and summer seasons. The good news is an easy application of fertiliser plays a key role in boosting vibrancy and lush growth if you're looking at lawn care options to enhance your grass.

We asked two leading lawn care experts to share their advice on how to fertilise a lawn, including how to prep your lawn beforehand, how and when to apply fertiliser, what the best fertiliser options are, and how often you need to feed your lawn for the best results. Here's what they have to say.

Step-by-step tips on how to fertilise a lawn

Our lawn care experts are Cheryl Harper, managing director of Greensleeves Lawn Care, and Richard Barker, horticultural expert at LBS Horticulture. First they outline the five key steps on how to fertilise a lawn, including the vital prep stages.

1. Assess your lawn

When the weather starts to warm up and the grass begins to grow again, take a good look at your lawn as it's the perfect time to give it some attention, including of course, fertilising it.

“Before applying fertiliser, check the condition of both the grass and the soil,” says Cheryl. “Identifying issues such as thinning grass, discolouration or compacted soil helps ensure the right nutrients are applied in the right way.”

2. Mow and clear debris

Regular mowing helps to keep the lawn growing strongly and deters weed growth. It's also a key step before fertilising the lawn.

“Cut the grass to an appropriate height and remove leaves or debris so the fertiliser can reach the soil surface and be absorbed properly,” says Cheryl. “In autumn and winter, when the weather is cooler, mow to a height of 25 to 40mm. In spring and summer, mow to a height of 10 to 25mm.”

Richard points out that a few days prior to fertilising is the best time to mow the lawn.

3. Prep lawn by scarifying and aerating it

It’s also important to scarify the lawn by raking it with a spring tine rake or using a scarifier. “This will remove any thatch buildup, as this can stop fertiliser from reaching grass roots,” says Richard. This will also get rid of lawn moss. Again, be sure to clear away any debris that might hinder the fertilisation process.

“Next aerate the soil by using a garden fork or hollow tine aerator to spike holes at regular intervals in the lawn,” says Richard. “This will ensure that the fertiliser can reach the roots of the grass in order to promote proper growth.”

4. Apply the fertiliser evenly

Feeding a sparse or struggling lawn with a specialist fertiliser can give it a real boost. Apply the fertiliser evenly, ideally on a cool day when rain is expected.

“To help spread your chosen fertiliser use a broadcast or drop spreader for granular products, or a sprayer for liquid feeds, to avoid patchy results or scorching,” says Cheryl. It’s a good idea to wear protective gloves.

“Apply the fertiliser to your lawn according to the manufacturer's instructions and water your lawn afterwards if no rain is forecast,” says Richard.

5. Caring for your lawn afterwards

“Light watering helps nutrients move into the soil and down to the root zone, where the grass can absorb them more effectively,” says Cheryl. “Over the following weeks, observe how the lawn responds and plan further applications as needed to maintain consistent, healthy growth.”

Check for even growth and any patches that look bare. If the lawn growth does look inconsistent consider a second application to even out the result.

Cheryl Harper

Cheryl Harper is the managing director of Greensleeves Lawn Care. Established in 1998, Greensleeves is a lawn care franchise that delivers a year-round service through an extensive network of franchisees across the UK.

Richard Barker

Richard Barker is an expert in horticulture at LBS Horticulture. He is keen to share his knowledge with both experienced and beginner gardeners, and prides himself on keeping up to date with the latest horticultural trends.

Types of lawn fertiliser

There are lots of different lawn fertilisers on the market. You can get both liquid and granular lawn fertilisers, as well as specific feeds for spring and autumn that contain different levels of nutrients according to the season.

Each type of fertiliser has its advantages, and the best option depends on your lawn’s specific needs.

To simplify things Richard Barker has come up with the following list:

• Slow release fertiliser This provides the lawn with nutrients gradually over the course of a few weeks or months. This can prevent sudden growth spurts and scorching, and usually consists of granules that will gradually break down when exposed to heat or water. This can be an easy fertiliser to use, as a single application can feed a lawn for a long period of time.
• Quick-release fertiliser High in nitrogen to give grass a quick boost when rapid growth is required. However, the quick release nature of this type of fertiliser means that repeated applications are needed, and they also need to be applied carefully so that they do not scorch the grass.
• Liquid fertiliser Sprayed onto grass so it's absorbed quickly through roots and leaves. As it delivers nutrients rapidly, you may see results within days. It can be a better option than granular fertiliser, as it's usually lower in nitrogen and has less risk of scorching the lawn.
• Granular fertiliser Takes the form of small, solid pellets that are watered into the grass. They usually act more slowly than liquid fertilisers, but can provide a consistent, long term supply of nutrients.
• Weed, feed & moss killer Another granular fertiliser, this weed and feed option also kills weeds and moss as well as fertilising the lawn in a single application.

Further to Richard's advice, Cheryl points out there is also a difference between organic fertilisers and synthetic fertilisers.

"Made from natural materials, organic fertilisers release nutrients slowly, improve soil structure and support long-term lawn health. Chemically formulated synthetic fertilisers deliver nutrients more quickly, providing faster green-up and visible results."

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When to fertilise a lawn

If you're looking for when to add fertilising tasks to your lawn care calendar, spring is one of the most important times to fertilise a lawn. "As grass begins to grow more actively, it often lacks nutrients after winter," explains Cheryl. "While sunlight supports growth, grass also relies on nutrients in the soil, which can become depleted if not replenished."

Applying a lawn feed in spring helps thicken the grass, improve overall health and restore a rich green colour, giving the lawn a strong foundation for the months ahead. If you have patches you will also need to overseed your lawn in addition to using fertiliser.

Fertilising a lawn is best between the months of March and October, as it is during this period when temperatures increase and the grass will be actively growing. "It's not recommended between November and February," says Richard, "as your lawn will be growing very slowly or not at all if it has entered dormancy."

So a good plan is to fertilise your lawn at the start of spring, in summer for a quick boost, then again at the beginning of autumn to support the grass throughout the dormant season. Always check the weather forecast as rain can wash away the fertiliser before it can take effect.

FAQs

How often should you fertilise a lawn?

How often you should fertilise a lawn depends on factors such as the condition of the lawn, soil type and climate. "For most UK lawns, two to four applications per year is typical, usually in spring, early summer, late summer or early autumn," advises Cheryl Harper from Greensleeves Lawn Care.

This approach to fertilising a lawn provides a steady, balanced feed throughout the year, helping to avoid sudden growth spurts and reduce wasted nutrients. "The result is stronger, healthier grass that stays greener for longer, even in challenging weather."

If you're also interested in making your garden more eco-friendly Angharad James, brand manager at Maxicrop® has the following tip: “Seaweed-based products provide a natural way to strengthen lawns, particularly during colder months. Seaweed contains natural plant growth hormones that promote strong root growth and help maintain healthy blades."

Using a product like can also support soil health by feeding beneficial microbes, improving nutrient uptake and soil structure. This means lawns benefit from faster germination, stronger roots and a hardier, greener finish, keeping them robust throughout winter and ready for spring growth.

To smarten up your lawn further for spring and summer, consider spending time on your lawn edging ideas to create a neat finish that can also help to prevent path and patio weeds from spreading to the grass.