As you run your lawnmower – blades of cut grass are constantly being “whipped” against the inside of the mower. Over time, this causes a build-up of grass underneath the mower that you’ll eventually have to wash or scrape off. So goes the age-old question; how to keep grass from sticking to mower deck.
Luckily, there’s a simple way to keep your mower deck clean and in proper condition. Today we will show you how to do that – and also provide a few mowing tips along the way!
Why Is Grass Buildup Bad?
Grass build-up can cause a variety of problems once it gets thick enough. To begin with – Grass build-up will affect the efficiency of a mower. A mower’s ability to cut more grass and the overall performance of the mower inhibits airflow throughout the deck.
Lawn Mowers Use “Airflow” to Operate Efficiently
By design, mowers need adequate airflow to operate correctly. The blades of grass won’t get sucked up into the mower deck efficiently and the mower blade will not cut the grass adequately.
If grass build-up is bad enough it causes friction and resistance on the mower’s ability to cut grass, and it can even strain the mower’s engine and cause it to bog down.
In a worst-case scenario, grass build-up can even cause a mower deck to rust out. This is because the built-up grass traps moisture against the metal mower deck and hold it there.
Moisture Causes “Rust”
Given enough time, that moisture will cause rust, eventually making the mower unusable if left unchecked.
Ok, now we know why it’s important to keep grass from building up inside your mower.
Let’s take a look now at some simple steps you can follow to prevent grass build-up on your mower.
5 Steps – How To Keep Grass From Sticking To Mower Deck
Step 1: Access and “Clean the Mower Deck”
Before you can do anything else, you need to get under your lawnmower and give the underside of the deck a thorough cleaning. Some mowers have a hose attachment built-in to the top of the deck. If yours does, you can use it to clean out the underside of your mower deck as you normally would.
However, If you need to clean the deck by flipping it over, here’s our recommendation.
First, disconnect the spark plug before turning it over to prevent damage and ensure your own safety.
Next, tip the mower over and keep the gas and oil reservoirs kept on the top side to avoid spilling. You should also consider emptying the gas tank, before cleaning the mower.
Household Tools to Clean Mower
To clean the deck thoroughly, First spray the underside of the deck with a hose and let it soak for 5-10 minutes to soften up.
Then, Using a stiff plastic putty knife remove the heaviest grass build-up followed by a soft bristle brush and soapy water – to remove remaining grass.
Note: Never use a wire brush. A wire brush will scratch the manufacturer’s paint on the mower deck – eventually causing rust – which creates the perfect “catch” surface for grass build-up.
Make sure all of the old grass has been removed from the deck – then proceed to the next step.
Step 2: “Repaint Mower Deck” ?
Lawn Mower manufacturers apply baked-on enamel paint to the entire mower deck. This paint is essential to avoiding grass build-up.
Remember, you want the grass blades to “slide” off the mower deck. Anything that hinders that – will cause the grass to “stick.”
If your deck underside paint of your mow is in bad condition – we highly recommend re-painting it with lawnmower paint.
The suggestions we offer below will have less value for how to keep grass from sticking to the mower deck if the paint on your mower is severely scratched or rusted.
Step 3: “Apply Coating” to Avoid Grass Build-Up
The reason that grass builds upon the underside of a lawn mower is that the surface allows it to stick. Once one layer of grass has built up, others can gradually accumulate on top of it, until you have thick layers of grass caked on your mower deck.
Lawn Mower Deck Spray
The best and easiest way to prevent this is to apply a spray lubricant that will keep the grass from sticking in the first place.
One of the most popular options for lubricating the underside of your mower deck is Dupont Teflon non-stick, dry-film lubricant. This spray lubricant while not designed specifically for use on lawn mower decks and blades is one of the most economical and highest-rated sprays to avoid grease, grime, and dirt build-up, and it works amazingly on mower decks as well.
Other top-rated products – branded as a spray-on lubricant for mower decks include Tite-Seal for mower decks sold at Amazon.
By evenly coating the mower deck in a layer of this lubricant after it has been cleaned and allowed to dry – you can dramatically help repel grass build-up.
Home Remedies To Coat Mower Deck
If you don’t have a specialized spray, there are any number of other “home” lubricants that will work well enough to get the job done. A few of the available options include WD-40, vegetable oil, and non-stick kitchen spray. Motor oil can also work, but it has a habit of dripping off after a while – and wouldn’t be our first choice.
If you choose to use a non-spray oil, be sure to rub it into the surface of the mower deck with a rag to ensure complete coverage and maximum adhesion. Clean off any excess non-spray oil before using the mower.
Graphite Coating for Lawn Mower Deck
A final option for preventing grass build-up is to use graphite spray coating. Graphite is a commonly used industrial lubricant and it also does a great job preventing grass from sticking to your mower deck.
As with any other spray or lubricant, be sure you’re starting with a completely dry – clean deck. Most graphite sprays dry fairly quickly, but there will be a brief period of about 30 min. required for drying when using graphite.
To be sure you’re applying the spray correctly, thoroughly read and follow all directions provided on the bottle.
Step 4: Change “Mowing Habits” to Prevent Future Build-up
Even with a lubricant on the mower deck, grass will eventually build up – given enough time and the right conditions.
To maximize the amount of time between mower deck cleanings, here are a few simple new suggestions to improve your Lawn Mowing Habits:
Wait For Grass To Dry
First and foremost, you should always wait until your grass is completely dry to mow it. Mowing after a rainstorm or in the morning after a heavy dew will introduce more moisture into the clippings and make them more likely to stick together.
Set Your Mower Height On Higher Setting
It’s also a good idea to set the height adjustment on your lawnmower higher. We recommend using a 3″ height if your mower can go that high.
Also, If you use your lawnmower on a short-setting height to “scalp” your lawn – you create much longer blades of grass – and of course more chance for build-up under the deck.
Mow Grass More Often
If you raise your mower deck and opt for slightly longer grass, you’ll find that you may have to mow more often – 5-day vs. a 7-day interval for instance.
Incidentally, when you keep your grass longer, it keeps shade at the roots and creates a much healthier, thicker greener lawn.
Step 5: Maintain Lawn Mower “Deck Coating”
Once you’ve coated your mower deck with a lubricant, it’s essential to maintain that coating over time.
Routinely, attempt to keep the mower deck dry and avoid running over sticks and twigs as much as possible, as either water or impacts from solid objects will wear down the coating over time.
From time to time, re-apply deck coating to keep the mower deck in optimal condition. We recommend re-applying coating at least every 24 mowings. This should keep your deck underside free from grass build-up.
How To Clean Riding Mower Deck With Wash Port
Because it’s difficult to access the bottom of a Riding Lawn Mower deck – most newer riding lawn mower brands feature one or more “wash port” locations for cleanout. To use the wash port feature to clean riding mower deck, follow these simple steps:
Start your Riding mower and move it to a flat and open area of your lawn – and away from buildings.
Attach the wash port adapter that came with your riding mower to your garden hose (if you don’t already have your local dealer should)
Attach the garden hose with the adapter to your mower wash port on the
Turn on riding mower, and dis-engage the mower blade(s), leaving the mower running.
Turn water to garden hose/water port on full.
Sitting on riding mower, engage the mower blade(s) and let run for 4-5 minutes to remove built-up grass clippings and debris from the underside of mower deck.
If you have more than one Wash Port on your riding mower – remove the garden hose and Repeat Steps 3 – 6 with additional wash ports.
If your mower only has one wash port, you’re done!
TIP #1: While some riding mower owner’s use the wash port “every time” they mow, we recommend doing this routine maintenance at least 2-3 times per season.
TIP #2: Visually check the underside of riding mower deck occasionally, by raising the front wheels up, some folks use a nearby curb, either way, choose a safe method. Using a flashlight inspect the underside of the mower deck and scrape any grass build-up not removed by using wash port cleaning method.
Frequently Asked Questions:
Does it help to replace the mower blade?
Many manufacturers include a standard mower blade with the sale of their equipment. Especially for budget models.
If you find your mower – after cleaning – is still not cutting properly, go online or your local hardware store and get a “High-Lift” mowing blade. These types of blade will create more airflow and lift, allowing more time to adequately cut the grass.
Should I run a mower on full-throttle or slower speed?
Most modern-day mowers are designed to run at full-throttle. For the purposes of this article, it is inherently important to do so. Full-throttle motor speed creates the maximum lift and cutting ability for your mower. These factors both contribute to less build-up as grass clippings get ejected quicker.
As a result of these tips – your lawn mower will run much more efficiently, and your maintenance time will be cut down dramatically. You should also be able to increase your walking speed – that is, without bogging down your mower and leaving those tell-tale “trails” behind.
Now that you know how to keep grass from sticking to mower deck undersides, you might actually “like” mowing again. After all, It’s a win-win-win – when you spend less time mowing, and cleaning, and get a healthier lawn along the way!
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References & Additional Reading
Here’s a quick video from WikiHow on cleaning a lawn mower deck
Looking for a New Mower? The Best Self-Propelled Mowers you can buy
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