Lawn fertiliser guide to help your grass flourish

Give your garden a boost with the best lawn fertilisers to feed your grass.

Man standing with rake looking at lawn

by Natalie Corner |

If your grass is lacking in colour and looking a bit pale, it's likely the soil needs feeding with lawn fertiliser.

While you can opt to spread grass seeds if you want to fill in those unsightly bare patches, lawn fertiliser encourages growth where grass just simply needs reviving, making it look thick and lustrous once more.

Employing the help of fertiliser will help your grass stay strong, keep its colour and continue to grow. The crucial thing here is knowing exactly what lawn fertiliser to use that will give you a lawn with lasting health, and that won’t be environmentally destructive.

It’s not just about attending to the nutritional demands of your lawn, you need to care for the microorganisms and overall soil health, too. In a forest, this happens naturally when dead flora and fauna break down, but in a tidy garden, that doesn’t happen.

That’s why we’ve created this guide to help you choose effective, sustainable fertilisers for your lawn. Please scroll down for fertiliser FAQs, including what NPK is, when and how to fertilise your lawn and fertiliser alternatives.

The best lawn fertilisers for your garden

Envii Seafeed Xtra - Organic Liquid Multipurpose Seaweed Fertiliser

Best liquid lawn fertiliser
Envii Seafeed Xtra

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SeaFeed Xtra is a premium, organic seaweed fertiliser that promotes strong, lush growth for plants and lawns and improves the biological activity in the soil. Seaweed also has iron in it, which gives extra greenness to your lawn. You can use this product on other crops, flowers, and indoor plants too. It comes in one, five, 10, and 20-litre containers that are made from recycled ocean plastic

Review: "I plant trees on behalf of the Woodland Trust and some of those recently planted were showing signs of distress due to the continuing lack of rainfall and very hot conditions. After reading reviews for this product I have begun using it whilst watering the trees. The results are quite amazing. Over the course of ten days, new leaf buds are appearing from areas that previously looked dead. Cannot recommend this product strongly enough."

Just Grow 'DUO' Organic Fertiliser - Seaweed and Chicken Manure Pellets

Best organic lawn fertiliser
Just Grow DUO Double Organic Fertiliser - 5kg

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This is a combination of seaweed and chicken manure. The seaweed acts as a supplement in improving soil quality, while the chicken manure acts as a stimulant for attracting bugs and worms. It comes in pellet form and can be used with any crop, not just lawn. One kilogram covers about 10 square metres.

Plantworks Ltd Empathy Lawn Feed Liquid Seaweed Stimulant

Best natural lawn fertiliser
Supreme Green

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This concentrated liquid feed is based on seaweed extract derived from sustainably harvested kelp, manufactured using a unique cell burst process. This process ensures maximum retention of the growth stimulants found in kelp along with a wide range of nutrients, vitamins, and amino acids. The feed also contains additional added nutrients in the form of nitrogen, phosphorous, potassium and iron to help maintain a healthy green lawn that is resistant to the emergence of weeds and moss. This product is endorsed by The Royal Horticultural Society.

Review: "This is an excellent product that, once established, produces lovely rich green grass to make a lawn anyone would be proud of. I had previously used Empathy Supreme Green Lawn Seed when I created a fresh lawn at my previous property. Within just a few months I had a lawn that was the envy of the neighbours (and of course I didn't let on that this was the 'secret' product I'd used). Anyway, the lawns around the house we've recently moved into had bare patches - so it was a no-brainer really when it came to choosing this product again to repair my lawn, with a view to bringing it back to life. And, just like before, I'm very pleased with the end results."

Westland SafeLawn Natural Lawn Feed

Best pet-safe lawn fertiliser

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Westland SafeLawn is a child and pet-friendly natural lawn feed that contains 100% natural ingredients that will thicken and green your lawn, resulting in the grass naturally preventing the growth of weeds and moss. Westland SafeLawn contains fast-acting and long-lasting plant nutrients, friendly bacteria to break down dead leaves and moss, and added grass seed to fill gaps and thin areas. When using this product, you can expect that in seven days, your lawn will become greener and healthier.

Review: "Mowed lawn Sunday afternoon, sprinkled by hand the granules afterwards. Weighed out the amount per m² and marked the paper cup where the level was roughly. One-handed sprinkling, right-handed shaking and spreading, left hand holding cup, through some disposable gloves and gaps between fingers. Sprinkled water with the hose after spreading and sprinkled once more on Tuesday. Today is Thursday and I already noticed it working on the dandelion roots I've removed with a tool. My cat is a happy chappy too, rolling around in the iron/blood granules, to no ill effects."

Miracle-Gro Evergreen Complete 4 in 1 Lawn Food

Best rated lawn fertiliser
Miracle-Gro Evergreen Complete 4 in 1 Lawn Food

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This is top-rated on Amazon for a reason. With over 13,000 reviews of an average of 4.4 stars, Miracle-Gro Evergreen Complete lawn food creates a thicker, greener and healthier lawn whilst killing weeds and moss. The one-stop solution promises results in as fast as seven days.

Review: "This is a fantastic product. Last year having used another product, which killed large sections of my grass and not the weeds, this product was easy to use and did not kill my grass. The moss was dead within a week and the other weeds, which there were a lot of, including dandelion, daisy, clover and other unknown weeds mostly all gone after 3 weeks. I just used a roundup spray for the odd weed, which was left and now have a lovely weed-free healthy lawn."

Lawn fertiliser FAQs:

When is the best time to fertilise my lawn?

It's recommended to fertilise your lawn twice a year, between late March and April, in the early summer, and once more in late autumn. For best results, apply fertilisers when the soil is moist, or when rain is expected.

What are the types of lawn fertiliser?

Synthetic formulas - Chemical fertilisers that offer immediate release and quick greening of the lawn, but at the expense of long-term soil health. These are manufactured using fossil fuels. They tend to be cheaper.

Organic formulas - Naturally made from once-living organisms or their by-products. These are not as fast-acting as synthetics, they release their nutrients more slowly. This is better for your garden's long-term health if used properly.

Other aspects to consider are:

Granular fertilisers - A popular choice due to the ease of application.

Liquid or water-soluble fertilisers - Spread using a hose, providing a quick and effective way to introduce nutrients rapidly to grassroots.

How to fertilise the lawn

Your lawn will get the most benefit from a fertiliser when you've just mown the grass. By feeding the newly shorn lawn with fertiliser, it will give the grass more time to absorb the nutrients before the next mow. If you mow your lawn after fertilising, you may disrupt the fertiliser before it has a chance to sink in properly.

You should not fertilise dry turf – there should be moisture in the soil for the grass plants to be able to take in the nutrients.

How you apply the fertiliser product will likely depend on the product's individual instructions, but for the most part, you can use a watering can for liquid fertiliser or spread it by hand if you are using granules.

Some lawn fertilisers may come with spreaders to make it easier to get an even distribution of feed across your lawn. You can also buy spreaders separately.

Should I water after fertilising?

Yes, always water your lawn before and after fertilising - or wait until it is due to rain.

What is NPK?

NPK stands for nitrogen (N) phosphorus (P) and potassium (K). When you buy a commercial fertiliser, you will see an analysis of the NPK content on the packaging.

You will generally see an NPK ratio on the label such as 7:4:7, for example. This is the percentage of nitrogen, phosphorus, and potassium in the product. These ratios vary from product to product, but as a rule, you want to avoid anything with high percentages. This is often reserved for cheap synthetic products that offer a quick fix.

What are alternatives to fertiliser?

There are alternatives to packets of fertiliser if you want more natural ingredients:

Chicken manure is great for encouraging bugs and worms in the soil. It smells a bit, so best to apply it in cooler weather and when damp.

Grass mulch is great for helping retain the ground's moisture and encourage worms. If your lawnmower has a mulcher already then that's even better because it's free. But just be wary that it can encourage more weeds.

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