What Is Mulching Grass? Benefits, Methods & Tips Explained

Did you know you can feed your lawn for free? That’s right, no fancy fertiliser, just your grass clippings. Because clippings break down and give food to the soil, they make a great way to keep your grass green and healthy. And let’s not forget, it costs nothing.

With this detailed guide, we will help you learn what mulching grass is exactly. You will also discover why it matters and how to do it well.

What does mulching grass mean?

In short, you mow the lawn and let the clippings fall back. You don’t collect them in a bag. Instead, you cut them again into tiny bits with the mower. Because these bits are now very fine, they break down fast and feed the soil. They are basically free compost now and keep the soil moist, fed, and help the grass stay strong.

It’s obvious that mulching is good for your garden, however, sadly, it doesn’t work for all kinds of lawns. You should avoid it if the lawn has thick thatch. Also, skip if the soil drains badly or feels hard and compact. Grass mulching is also not the best choice for lawns that get heavy foot traffic or grow in deep shade. In those cases, clippings may rot slowly and cause problems later on.

So, what happens if you don’t mulch? Then you need to replace the lost nutrients with good old manual work and money on fertilisers.

What’s the difference between mulching and mowing?

The trick is what happens to the clippings after you mow. Regular mowing doesn’t actively recycle nutrients back into the lawn. With regular mowing, you cut the grass and leaves or remove the clippings without breaking them down further. Mulching uses the mower to chop the clippings into tiny pieces that decompose quickly and feed the soil.

Grass mulching benefits for the lawn

There are quite a few grass mulching benefits...

Nutrient recycling

When clippings break down, they give back key nutrients. Nitrogen is the big one as it helps the grass grow lush and green.

So, mulched grass clippings act like a slow-release feed. You do not need to buy as much fertiliser when you have them at your disposal.

Moisture retention

Mulching grass is quite beneficial in hot weather. A fine layer of mulch shades the soil and slows water loss. This helps the grass cope better in dry spells.

On the other hand, non-mulched lawns often dry out faster.

Weed control

Mulch can stop many weed seeds from sprouting. The clippings form a thin cover that blocks sunlight. Less light means fewer weeds.

A mulched lawn also tends to have fewer bare patches, so weeds have less space to grow.

Reduced garden work and green waste

When you mulch, you skip the bagging or raking after each mow. It also means less green waste for the bin. Many local councils appreciate this, as it fits with their waste reduction goals.

Cost-effective lawn care

Mulching grass saves money in several ways. First, you spend less on chemical fertilisers because the clippings return nutrients naturally. Second, you save time and effort, as there’s no need to bag or dispose of the clippings.

Less green waste also means lower council bin charges in some areas. Over a full season, these small savings add up, making mulching a cheap and eco-friendly way to care for your lawn.

Are there any disadvantages to grass mulching?

The main disadvantage of mulching is that it does not suit every lawn. If the grass is too long or wet, clippings can clump and smother the lawn.

And what are the disadvantages of mulching mowers? They can leave more mess if the mower blades are blunt or the grass is damp. Some people also find they need to mow more often, as mulching works best with short clippings.

In this line of thought, another question also comes to mind: “Does mulching your grass cause thatch?”. In most healthy lawns, no. The clippings break down fast and feed the soil. But if the lawn already has heavy thatch or poor drainage, then mulching can make the layer worse.

How exactly does mulching grass work?

So, you finally want to try it for yourself? Here is the simple answer to the question of how mulching grass works:

Step 1: Find the right mower

It’s fair of you to ask if you can mulch with a regular lawn mower? Yes, if you fit a mulching kit or a mulch plug. As far as blades go, you can mulch with regular blades, but the results will be poorer. A true mulch blade cuts finer and spreads better.

A true mulching lawn mower has a closed deck and a mulch plug. It also has blades that lift, cut, then recut the grass into tiny bits.

Ok, but how do you know if the mower you already own is a mulching mower? Look for a mulch mode, a plug in the discharge chute, and a blade with extra cutting edges. The manual will say “mulch”.

Step 2: Mow when the grass is dry

Only mulch on a dry lawn. Late morning or early evening works well after dew lifts. Wet grass forms clumps and may smother patches, so that’s why you should avoid it.

Step 3: Cut no more than one-third

Never remove more than 1/3 of the blade in one pass. A lighter cut gives finer clippings and less stress on the turf.

Step 4: Set the mower height

Avoid scalps. For most UK lawns, set 4 to 6 cm (about 1.5 to 2.5 inches). Taller grass shades the soil and hides the fine bits.

Step 5: Mow on a steady schedule

Mow every 7 or 10 days. Do this from April to October.

You already know how often to mow the lawn, but do you have to mow slower when mulching? A little bit, yes. Keep a steady pace so the deck can recut the blades. If the engine strains, slow down.

Step 6: Overlap the rows

Overlap each pass by a few centimetres. This spreads the mulch thin and evenly. Avoid thick lines or piles.

Step 7: Inspect the lawn after the mowing

What does mulching grass look like when done well? You see no big clumps and the lawn looks tidy from a step or two away.

If you spot heavy patches, make a second pass at right angles. Another thing you can do is rake the area to spread the bits thin. Then watch the lawn for two to three weeks. You should see good colour and steady growth.

Extra tips for better results

Keep the blades sharp. Sharpen them every 25 hours of use, or at least once each season. Dull blades tear leaves and leave rough bits that break down slowly. 

Aerate once a year in spring or autumn to help the soil breathe. Add a light, seasonal fertiliser if a soil test says you need it and water in long dry spells.

What’s the best time to mulch in UK?

In the UK, the main mulching season is April to October. This is when the grass grows steady and can use the extra feed from clippings. The ideal rate is once a week during peak growth. This keeps the clippings short so they break down fast.

Now that you know when you should mulch a lawn, you also need to know when NOT to:

If you mulch grass late in the year, you can still leave clippings in early autumn. They feed the soil before winter. But when should you stop mulching the grass? Once growth slows and frost comes, switch to bagging. This keeps the lawn clear and tidy for the cold months.

Common myths about mulching grass

Myth #1: “Mulched clippings will smother my lawn”. This is only true if you leave big piles of wet clippings on the grass. With proper mulching, the bits are fine and spread out. They let air and water reach the soil. They also break down in days, not weeks. A healthy lawn can handle a thin layer with no trouble.

Myth #2: “You should never leave clippings on the lawn”. When you mulch grass the right way, clippings give back nitrogen and other nutrients. The key is short, even clippings not clumps. Otherwise, the clipping will hinder your soil.