How to topdress a lawn: why, how, and when?

Just when you thought your lawn care tasks were done for the year, you remember topdressing (or we’re reminding you now!). After all, topdressing your lawn is one of those lawn care tasks that always seem to end up at the bottom of the list (and never gets done). 

Topdressing your lawn CAN be costly, time-consuming, and challenging work. But the results are stunning. 

In this article, I’ll explain why you should topdress your lawn for excellent results. I’ll talk you through how to do it and the optimal window of the year for the best results. 

Ready?

Let’s get topdressing! 

What is topdressing a lawn?

Lawn topdressing is a process of adding beneficial material to your lawn’s surface. But there’s no one-size-fits-all solution — read on to find the ideal topdressing recipe to suit your turf. 

The benefits of top dressing are:

• Levelling the lawn surface — all lawns eventually develop bumps and dips. Topdressing helps heal uneven lawn surfaces. 
• Thatch control — thatch is the layer of organic matter that develops over the surface of your turf and, left to its own devices, can suffocate your lawn. If you use the correct topdressing “recipe”, you can minimise thatch. 
• Soil improvement — topdressing helps minimise soil acidity and bring fresh nutrients to your garden earth.
• Improves drainage — heavy clay soils become boggy in wet weather; topdressing your lawn (in combination with aeration) helps strengthen your lawn’s drainage.
• Aids overseeding and renovation — topdressing with the correct balance of nutrients can help boost germination while helping your lawn recover after scarifying.
• Boosts overwintering — the correct balance of nutrients added to the soil surface helps protect your grass plants during a particularly harsh winter. 

Topdressing a lawn: considering the “root zone”

Anything you add as topdressing eventually sinks to the “root zone” — the segment of soil where roots prefer to spread and grow. This makes it essential to use the correct topdressing material because it will eventually boost (or hinder) your grass’s roots. 

For example, a topdressing of sharp sand will have little to no benefit for heavy clay soil because it resists blending. 

Why topdress your lawn?

The principal benefit of topdressing your lawn is levelness — it helps cure the bumps and hollows that develop over time. 

For example, your lawn dips in areas of heavy use. If your kids have a goal post, the soil around the goal area becomes compacted. If you have an “unofficial” path from the house to the bottom of the garden, your grass eventually grows thin, and the soil becomes heavy and compacted. 

Topdressing can help address this unevenness, although it may take some time to handle severe bumps or hollows. 

Ultimately, topdressing isn’t just for lawn purists — all lawns benefit from additional nutrients. 

Topdressing a lawn: which materials to use

The best topdressing material is a mix of compounds, selected and mixed to benefit your individual garden’s soil. These range from sandy loam to heavier loam. 

Choose a sandy loam topdressing for heavy clay soil to assist drainage or a heavier loam for easily-drained sand soils to provide better nutrient and water retention. 

The three components of topdressing are:

1. Sand
2. Peat
3. Loam

Topdressing: Sand

Sand for topdressing should be of a medium particle size — too fine, and it becomes too claggy and suffocates the soil; too coarse, and it just lets nutrients drain away. Sea sand isn’t recommended as it’s too high in lime. 

Sand is particularly useful for levelling or smoothing your lawn’s surface and helps to lighten heavy clay soil. 

Topdressing: peat

Peat is a controversial compound for domestic gardening, as it is one of the planet’s most valuable stores of carbon dioxide, helping keep this potentially harmful gas out of the atmosphere. 

In situ, peat bogs store a colossal amount of carbon dioxide from the air. And undisturbed, peat is a valuable storage system. But when peat is disturbed, the carbon dioxide stored within the earth is released into the air. 

European peat bogs were formed from the ancient decomposition of animals and plants, and scientists calculate that European peat bogs, fens, and marshes contain five times more carbon than our forests. 

Peat is used as a soil improver (although it’s actually not particularly nutritious as plant feed) or burned as fuel. But peat use in domestic gardening is a very short-sighted practice, heavily impacting air quality and the climate. 

In fact, the UK government will ban amateur peat use by 2024 — but luckily, there is a green alternative. 

Peat adds acidity to your soil, so you should use it for lawns sparingly because too much acid in the soil is excellent for weeds and bad for grass. 

However, peat used in moderation within topdressing mixes adds texture and water retention to the combination.

Topdressing: loam

Loam is a fertile, nutritious soil comprising equal parts of clay, silt, and sand. The loam used in your topdressing should be neither too sandy nor too heavy in substance. 

Loam top dressing is commonly used for cricket pitches, offering firmness underfoot and fertility for grass plants. 

Can I make my own topdressing?

Finding the correct balance of sand, peat, and loam is a delicate balance, and it’s probably better to buy it in – ready mixed in a blend explicitly curated to your soil type. 

Remember, whatever mix you use for topdressing eventually sinks into the root zone. 

If you’re mixing your own, consider:

• Your grass plant’s root zone
• What you want to achieve

For example:

• Sandy soil, prone to drought exhaustion in the root zone, needs water-retentive peat-based topdressing. 
• Heavy soils prone to flooding or becoming claggy benefit from a higher percentage of sand to aid drainage. 

Making your own topdressing mix

For sand-based soils

Sandy soils drain quickly and are prone to drying out during warm weather. They also become nutrient deficient as your lawn’s essential nourishment gets washed away. 

So, you need a better soil structure that retains water and nutrients. 

Go for:

• 4 parts loam
• 3 parts peat
• 1 part sand

For clay-based soils

Clay soils are heavy and prone to drainage issues during wet weather. However, clay-based soils tend to hold onto their nutrients well. 

So, you should aerate your lawn soil regularly to address the heaviness in the earth, and add topdressing with the following mix:

• 2 parts loam
• 1 part peat
• 4 parts sand

For loam-based soils

Loam soils kind of fit in the middle — the Goldilocks soil, as it were. So, loam drains well and holds onto water and nutrients well but doesn’t flood or get claggy.

Lucky you! 

We recommend the following mix for loam-based soils:

• 3 parts loam
• 1 part peat
• 3 parts sand

What type of soil do I have?

Find out your soil type in the following way:

1. Grab a handful of soil, and squeeze it in your hand. 
2. Release the squeeze, and look at the soil.

Then, take note:

• If the soil grains stick together and become surface-smooth when you rub your fingers over the top, you have clay soil. 
• You have loam-based soil if the earth has a velvety or floury feel.
• You have sand-based soil
•  if the grains don’t stick together and feel gritty. 

When is it best to topdress your lawn?

Topdress your soil only during growth periods. In the UK, that tends to be between April and October. But it depends on the weather; if the warm weather continues into November and your grass continues to grow, topdressing should also be OK.  

Most people topdress their lawns in early autumn or late spring as part of the renovation process — especially after aeration. 

How often should I topdress my lawn?

We recommend topdressing once a year, but it depends on your soil. If you have poor-quality soil, you can topdress more regularly. 

How to topdress your lawn: a step-by-step guide

It’s always a good idea to topdress after aerating your lawn, especially if you use a hollow-tine aerator. The top dressing falls into the holes in the soil and gets closer to the root zone, nourishing your grass plants where they need it!

Topdressing your lawn: Step 1 — mow

Mowing your lawn helps the topdressing to reach the soil surface. It gets stuck in long grass. 

Topdressing your lawn: Step 2 — spread 

Spread your topsoil mix over your lawn’s surface, focusing on dips and hollows while aiming for an even spread. Make sure that both the topsoil and the grass are dry — never try and spread wet topsoil (or it will be like spreading Marmite on your grass!). 

Apply around 1.5-2kg of topsoil per square metre. Make sure it’s dry! 

It’s easier to spread evenly if you portion the top dressing into smaller batches and then concentrate on smaller lawn quadrants. And use more if you’re filling in gaps and hollows. 

Topdressing your lawn: Step 3 — rake 

Make sure the topsoil is dry. Then, use a rake to blend the topdressing with the top layer of soil. Repeat the process until the topdressing is less visible and has become part of the turf. 

If a rake isn’t getting into the swarth, use a stiff brush or a levelling lute. 

Topdressing your lawn: Step 3 ½ — overseed

I recommend overseeding with high-quality lawn seed AFTER topdressing. That way, you won’t disturb the seed as you rake it into the swarth. 

Once you’ve sown the seed, brush it very lightly into the loose upper dressing before rolling or firming the soil to ensure good soil contact. Water lightly regularly for the next couple of weeks to improve germination. Don’t overwater — you’ll just disturb the seeds. 

Topdressing your lawn: Step 4 — rest

No — not you! Let the lawn rest for a couple of days before walking on it. This will help keep the top surface beautifully level. If there hasn’t been any rain since you raked, water your lawn lightly to keep the soil moist and wash away loose earth that hasn’t taken. 

Topdressing: Aftercare

Aftercare is relatively straightforward. 

Give the lawn a week or so to bed in before you mow; otherwise, you could blunt your cutting blades on any topdressing that remains on the grass leaves. 

Then, sit back, relax, and enjoy the beautiful level surface of your lawn!

Any questions?

I hope you’ve got everything you need here to make your topdressing a successful venture. But if you have questions, please don’t hesitate to email us. 

We love to hear from you and promise to get back as soon as possible! 

Remember to share this article with your friends. Thanks for reading. 

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