Can You Put a Mulching Blade on Any Mower?

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Mulching is a great and inexpensive way to return the much-needed nutrients back into the soil.

Because of this, and a few other benefits, many people are turning to mulching mowers.

But lawnmowers are not exactly cheap, so what should you do if you already have a standard lawnmower that is not designed for mulching?

For most people in this situation, getting a mulching blade will be the best option.

But can you put a mulching blade on any mower? Yes, you can put a mulching blade on almost any mower. To put a mulching blade on a mower, the blade needs to be able to fit the deck properly and be secured tightly. Not all mowers equipped with a mulching blade will do a good mulching job due to bad deck design, or low-powered engine.

When changing the blade of a lawnmower however, some caveats need to be taken into consideration first, especially if this is the first time you will be changing your mower’s blade.

Below I share everything I have learned about switching to mulching blades.

What Separates Standard Lawnmowers From Mulching Lawnmowers?

The standard mowers are often referred to as 2-in-1 mowers because they are suitable for bagging and side discharging.

The majority of standard lawnmowers come with a standard blade, which is ideal for cutting short lawns.

The standard blades are very basic, their cutting and suction capabilities are mediocre, and they are not suitable for mulching.

In comparison, mulching lawnmowers are a bit more specialized.

They come with a specialized mulching blade, which is designed in a unique way.

The purpose of the mulching blade is to cut the individual grass pieces multiple times.

This is achieved by creating a better airflow that keeps the grass clippings under the deck and around the blades for longer. As a result, the grass is gradually cut up into smaller pieces before falling down into the lawn.

A good mulching mower also has a circular deck that should not have any edges or places where grass can get stuck. Often there is no discharge chute, so mulching mowers are rarely sold with a rear bag.

Can You Turn Any Lawnmower Into a Mulching Mower?

The good thing is that many of the standard lawnmowers can actually be adapted for mulching.

Usually, for the best results, you need to do the following:

  • First, you need to install a suitable mulching blade; and
  • Secondly, you need to add a restriction plate.

Conversely, if you block the chute, you can achieve some acceptable mulching levels even without a mulching blade.

This can happen if you have a plate or a cover that can be used to block off the discharge chute. But keep in mind that in this case, there will be a higher chance of grass getting stuck underneath the deck.

The problem is that the different models of lawnmowers do have different deck designs.

Because of that, effectively blocking off the discharge chute may be very tricky.

Additionally, a mulching blade on its own will not make for better mulching. Blocking off the discharge chute is necessary.

Failing to do so will result in poor mulching performance as grass clippings will end up being larger and side discharged or bagged (depending on the setup).

One of the usual ways to adapt a standard mower for mulching is by using a mulching kit.

What Is a Mulching Kit?

A mulching kit is a set of several accessories that, when installed on your lawnmower, will allow it to mulch.

The mulching kits can consist of a few different items like mulching blades, restriction plates, mulching baffles, deflectors, decals, the necessary tools needed for the installation, and instructions. However, not all of these may be included or even necessary.

To install a mulching blade, you need a blade that has the right dimensions.

This is why before buying a new lawnmower blade, you need to do several measurements and then decide on what blade you will need. I recently wrote an article about choosing the right mower blade, you can check it out here.

The restriction plate (also called restriction plug) is placed through the rear chute.

Its purpose is to block and deflect the grass clippings from being discharged through the chute. That way, the grass clippings will remain under the deck where the mulching blade will cut them and push them into the soil.

The bad news however, is that the restriction plates are not universal, and because of the design, different variants will not fit every lawnmower.

Before purchasing a mulching kit, make sure to check if it can be used with your lawnmower – mulching kits are usually designed for specific brands and models.

How Powerful Should the Lawnmower Be?

Not all standard lawnmowers are suitable for mulching.

Mulching can place a lot more strain on the engine. Thus, only mowers with at least five or more horsepower should be adapted for mulching.

Lawnmowers with less than four horsepower may not be able to produce enough torque to cut and mulch the grass clippings properly and therefore, should not be used for mulching.

Are There Different Types of Mulching Blades?

There are two different types of mulching blades.

Standard Mulching Blades

The standard mulching blades are easy to spot. They have a very distinct curved design.

The standard mulching blades create a relatively good level of suction and can cut the grass into tiny pieces.

However, mulching blades are not well suited for bagging or side discharging.

Gator (Toothed) Blades

The Gator blades are usually considered 3-in-1 blades.

They are a hybrid because they perform well in all three categories; mulching, side discharging, and bagging.

They are unique in that they have raised teeth behind the cutting edge of the blade. These teeth are designed to create superior air circulation and suction that will keep the grass cuttings under the deck and near the sharp edges of the blades.

Thus the Gator blades can produce extremely finely-cut grass clippings.

The Gator blades are frequently used on zero-turn mowers and mowers that have multiple blades.

How to Find out If the Mulching Blade Will Fit in Your Lawnmower?

Regardless if you have to get a new replacement blade or just a different type of lawnmower blade, you need to go through a few steps first.

These steps involve measuring and identifying certain characteristics of the blade.

  • Measure the length of the blade (this is done diagonally from cutting edge to cutting edge);
  • Measure the inner diameter of the center hole and identify the type of the center hole. Some center holes can come in different shapes and sizes (5, 6, or 7 point stars, H patterns, and more);
  • Measure the inner diameter and the distance between the centers of the two side holes (if the blade has any); and
  • Measure the thickness and width of the blade at its center.

All of these need to match the original blades your mower is designed to work with. Otherwise, you are risking getting a blade that will not fit correctly.

However, if you are unsure, one of the best ways to make sure that you will get a blade that will fit your lawnmower is always to take the user’s manual along with the blade itself to your local Home Depot store. That way, the people working there can quickly help you identify what mulching blade you need.

Is a Dedicated Mulching Mower Better?

A lawnmower that has been designed for mulching is almost always going to do a better job at mulching. Even a standard lawnmower equipped with a mulching kit will underperform compared to a mulching mower.

Although a mulching kit may be installed on many regular mowers, the problem will often be in the design of the deck itself.

Mulching mowers have closed off decks that are designed in such a way as to keep the grass clippings under the deck, improve airflow, and continuously push the grass clippings into the blades.

On the other hand, using a standard mower with a mulching kit has the added benefit of more versatility. You can install or remove the kit whenever you want.

So what are the alternatives?

Having two lawnmowers means spending more money on maintenance, and you will need more storage space as well. Also, a mulching kit is significantly cheaper compared to buying a second, dedicated mulching mower.

This is why homeowners that are looking for the best versatility can go with 3-in-1 or 4-in-1 lawnmowers. These multi-purpose lawnmowers are adapted for regular cutting and mulching of the grass.

For anyone who already has a lawnmower (preferably a very old one), and is tech-savvy, buying a replacement mulching deck in combination with a mulching blade may be a viable and cheaper alternative to purchasing a brand new mower.

What that means in practice is that you will be changing almost the entire mower and only keeping the engine.

What About the Warranty?

Before installing a new mulching blade on your mower, there are a few considerations you need to take into account.

Keep in mind that not all manufacturers allow for a different blade to be installed on their mowers.

For example, installing a mulching blade may result in the warranty being void by the manufacturer.

Check with the manufacturer’s warranty conditions before going that route.

Peter Toth

Hi! I'm Peter, the owner of BackyardGadget. Working around the house has always been a big part of my life. I've created this site to share my experience, and to help people choose the right tools for the job. Thank you for stopping by!