The Best Moss Killers For The Perfect Lawn

Gardeners in the UK seem to have a love affair with grass, and the perfect stripy lawn is something of a guilty pleasure for more than a few of us.

But how does one transform a moss-covered patchy grassy area into a lawn they can be proud of?

There are a few steps you’ll need to take to achieve this, but it all starts with a good quality lawn moss killer.

If you have a mossy lawn and you don’t treat it with a suitable moss killer that is specially created for lawns, the moss spores will just spread and the lawn moss will return – often with a vengeance.

We’ve got some great tips on how to achieve and maintain a moss-free perfect lawn, but first, check out the best moss killers for lawns, as rated by us.

1)  Iron Sulphate by Trade Farm

Iron Sulphate is the key active ingredient in dozens of expensive branded lawn moss killers and conditioners – it’s cheap, extremely effective at getting rid of lawn moss and also has several other benefits.

But why pay over the top for a branded product when you can buy pure Iron Sulphate for a fraction of the price?

2.5kg of Iron Sulphate currently costs less than £20 and it goes a long way.

Once you’ve diluted the granules, you’ll discover that 1kg creates an impressive 500 litres of product which you can apply by watering can or via backpack sprayer.

Key Points:

  • Safe for children and pets after 24 hours
  • Use a low dose for lawn feeding – a higher dose creates a powerful lawn moss killer
  • 1kg is suitable for small to medium size lawns
  • Sprinkle granules or dilute with water first
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2) EverGreen “No Rake” Lawn Moss Killer

Lawn moss treatment by Miracle GroMiracle Gro has been producing branded lawn and garden products in the UK for decades.

Their “no rake” lawn moss killer contains several different nitrogens, potassium and magnesium oxides as well as organic bacteria designed to eat away at the moss naturally.

This granular product is typically applied by hand or by rolling dispenser. The best time is just before rainfall between May and September.

Key Points:

  • You can spread the granules by hand as they will dilute after rainfall
  • Can be applied more frequently – every 3 months for maintenance
  • Ideal for smaller gardens – could get expensive for large lawns
  • One pack will treat 5m x 10m
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3) Maxicrop Seaweed Base Lawn Tonic and Moss Treatment

Maxicrop lawn moss killerMaxicrop is different from the two previous products we recommend – it’s water-based and not made from powder or granules.

2.5 litres of the undiluted product will treat 165 sq metres of lawn.

Maxicrop contains concentrated seaweed extract which has been a firm favourite with gardeners and lawn experts for decades. This product contains nitrogen and iron sulphates at relatively low dosages to complement the seaweed extract in killing lawn moss.

You can apply this mixture up to twice in any given year and experienced gardeners usually apply it once in the spring and then again in the autumn.

Key Points:

  • Contains seaweed extract
  • Liquid product, no granules to handle
  • Safe for children once dry
  • 1 bottle will be enough for a small/medium lawn for 1 year
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4) Lawn Sand by Westland

Lawn moss killer by WestlandLawn sand is a popular product that can be used several times per year and works very well as a maintenance product.

Although not always strong enough to kill off a carpet of moss, it works very well at maintaining a moss-free lawn assuming the moss has been removed previously.

This product contains nitrogen to feed the grass and ferrous sulphate to treat moss growth.

One 20kg bag will treat 200 sq metres.

Key Points:

  • Sand and granules
  • Good maintenance product
  • Too weak to treat thick carpets of lawn moss
  • Cheap and available at most garden centres
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5) Bonus Product – Rotary Spreader

Rotary spreader for application of lawn moss killer and seedsYou’ll find that a rotary spreader is the easiest and most accurate way to spread seeds and granular feeds onto any lawn:

  • You won’t scorch the grass by dropping or over-applying a lawn moss killer
  • Saves money in the long term as you prevent wastage
  • No handling of fertilisers
  • Strong and sturdy so will last for decades
  • Makes application easy and quick
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Top Tips For Applying Lawn Moss Killer Products

Lawn moss killer products will work best if you follow the protocol listed below.

Apply the product in the wrong season and you’ll just be wasting your time and money.

While every product is different and you should always read the label, in general:

  1. Apply during April to early September avoiding heatwaves and dry spells in the summer.
  2. Do not apply more often than twice per year, May and early September are popular treatment times.
  3. Apply granules just before rainfall so they dilute and soak into the lawn naturally.
  4. Consider a milder maintenance product once you’ve killed off the bulk of the moss and the grass has grown thick.
  5. Keep children and pets off the grass until 24 hours after the lawn moss killer has soaked into the ground and dried.
  6. Use a spreader to ensure the product is applied evenly, this saves you money and prevents the scorching of areas due to over-application.

How You Can Prevent Moss Growth and Ensure Your Lawn Stays Beautiful

If your lawn contains an excessive amount of moss growth, consider making changes to your garden that improve drainage, aerate the soil and increase the available sunlight reaching the ground.

Those three points are the key to maintaining a perfect lawn, regardless of how much lawn moss killer and fertilizer you apply. Consider these carefully when planning a new garden design.

Here are several steps you can take:

Step 1 – Increase sunlight reaching the garden by trimming back or removing overhanging branches. Also, reduce tree/shrub height where possible. Consider fencing that allows some sunlight through if possible.

Step 2 – For stubborn shaded areas, consider a redesign of the garden space to increase borders, paths or patios leaving the sunny areas for the lawn.

Step 3 – Apply a lawn moss killer during early May and early September.

Step 4 – Once the moss has turned brown, scarify the lawn to aerate the top layer of soil, lift compacted ground and help with drainage. Explore our guide to scarifying and the best scarifiers here.

Step 5 – Apply grass seed for shady areas and cover them with mesh to stop birds from stealing them (optional).

Step 6 – Consider a milder maintenance moss treatment product once you have the moss under control and the grass is well established.

Can I Use a Lawn Moss Killer on Driveways and Patios?

Lawn moss killers often contain several ingredients that you probably wouldn’t want to come in contact with certain types of patio slabs.

Yellow/brown staining may occur, which may not show until several weeks or even months after the application.

For this reason, you should instead use Benzalkonium Chloride as it’s far less likely to react with hard surfaces. Use this on tarmac, slate and concrete as it’s 100% safe. For patio slabs, apply a test patch and leave for at least a few weeks before applying liberally.

Benzalkonium Chloride is a popular moss killer for hard surfaces and you’ll found on most garden centre shelves.

You should not apply this product to lawns as it will turn the grass brown.

Our review of Benzalkonium Chloride, which is based on over a decade of use can be found here.

This review of the best products to kill and prevent lawn moss was created by Claire Mitchell and is posted in the Gardener’s Corner – Updated 28th April 2022.

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