Are Four Blades Better Than Two on a Lawn Mower? (Discussed)

Lawn mower cutting through grass and daisies

Nowadays buying a lawn mower isn’t quite as straightforward as it used to be.

There are lots of optional extras or upgrades you now have to consider.

And it is one of these possible upgrades we will be dealing with today.

So are four blades better than two on a lawn mower?

Let’s find out…

Are Four Blades Better Than Two on a Lawn Mower?

It depends a lot on your lawn and personal preference as to whether four blades are better than two. Two-blade mowers tend to deal with denser, thicker grass better whereas four-blades are less likely to see your mower get clogged and will deal with mulching grass better.

I was inspired to write this after a good friend of mine bought a new Honda HRU19M1 lawn mower.

The mower came with two blades, but there was the option of having two additional blades installed on it to make it a four-blade mower.

He umm’d and ahhh’d over it before getting the two additional blades installed.

In all honesty, for the standard lawn, the difference is probably fairly minor, but there might be some occasions when four blades are better than two and vice-versa.

Are Two Blade Mowers Better?

So let’s start by looking at two-blade mowers.

Two-blade mowers tend to deal with thick grass better.

Adding an extra two blades doubles the sweep frequency of a mower, but it doesn’t change the energy at the point of contact when the blades hit the grass.

A four-blade mower will be cutting a lot more grass than a two-blade mower.

What that means is two blades should maintain the momentum of the engine RPM more effectively, whereas a four-blade mower might lose rpm and get bogged down in thick grass more easily.

Two blades will also rotate faster, theoretically helping cut thick grass, but they will most likely wear out more quickly.

Are Four Blade Mowers Better?

Mower cutting daisies and grass

Many commercial mowers have four blades, which would indicate there maybe is something in the claim that four blades are better than two on a lawn mower.

You get more cuts per revolution of the disc and double the suction.

If one blade gets damaged, you still have 75% of your blades working.

Having four blades adds to the draught, meaning damp grass will be more easily expelled as to opposed to get clogged in the mower.

If you keep your lawn fairly short and cut it regularly, four blades will probably be better as you can dial down the RPM of the engine.

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If you are mulching the grass then again four blades might be preferable. 

Often four blade mowers have two blades with a different angle on them. These lifting the grass clippings up and chop them even more times into a much finer output.

On the contrary, as mentioned above, four-blades could find it harder to cut thick grass and the additional blades may put the engine under a greater load due to the extra work it is doing.

Also in dry and dusty conditions, four blades will kick up more of a storm than two blades!

Finally there is the question of the updraft of air to get blades of grass standing vertically so they can be cut properly.

I’ve read some people say that the additional blade surface of four blades would mean less airflow, meaning the grass would not stand as high when being cut as a two blade mower.

But then I have also read anecdotal evidence to the contrary, so really I can’t say for certain on this point!

So Two Blades vs Four Blades – Which is It?

I honestly think for most lawns, two blades or four blades won’t make a difference.

You shouldn’t be choosing a mower primarily on whether it has two blades or four blades, there are other more important factors to consider.

I actually know of a couple of people who use four blades when it is the growing season and then switch to two blades when it starts drying out. So there is always that option.

That said not all mowers are able to accommodate an additional set of blades.

If you have always used two blade mowers without a problem then there is no need to change to four blades and vice-versa.

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Are More Blades Better on a Reel Mower?

A consumer cylinder mower, or reel mower as they are often known, can have anything from five to 12 blades.

So that leaves another question related to this article, are more blades better on a reel mower?

In theory, yes, the more blades there are the better the cut.

In practice, it is a little more complicated than that.

Because the more blades the mower has, the less efficiently it will deal with taller grass.

That is because as the number of blades increases, the space between the blades decreases.

So only shorter grass will tend to get into the reel.

Therefore if you buy a reel mower with 11 or 12 blades, you will need to keep your grass short and cut it regularly. The height of the cut is directly correlated to the frequency of your cut.

The mowers that are used to cut the greens on golf courses sometimes have up to 14 blades, but they are out on the course every day otherwise, within a couple of days, the grass on the green will be too long for the blades.

For a more detailed account of the ins and outs of this, then this Toro Reel Mower booklet is worth a read (especially pages 11 to 15).

The most common choice when it comes to a reel mower is a 5 or 7-blade reel. 

The explanation above shows why a 5-blade real is recommended for grasses that haven’t been cut in a while and coarser grasses like Kentucky Blue or Common Bermuda Grass and why a 7-blade reel is suited for lawns that are maintained every week. 

The wetter, taller and chunkier the grass the less blades you want.

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Final Thoughts

 Are Four Blades Better Than Two On a Lawn Mower infographic

As you can see from the infographic above there isn’t a yes or no answer to the question of whether four blades are better than two on a lawn mower.

There are a number of extenuating circumstances that will affect your choice.

But you shouldn’t select a mower solely on whether it has two blades or four, there are always a number of things you should weigh up.

If you have always used a two blade mower without any problems than stick with it, the same goes for a four blade mower.

When it comes to reel mowers though be aware that more blades will give a finer and closer cut, but also the more blades you have the less effectively they will deal with long grass.

I hope that helps!

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