How to Remove Grass Buildup from a Lawn Mower Deck

Submitted by Anonymous (not verified) on Thu, 10/21/2021 - 4:57pm

How can I maintain my lawn mower by removing grass buildup?

What causes grass buildup? How can I clean my mower deck? How can I prevent grass buildup from happening in the future? The answers to these questions will help you take care of your lawn mower.


Lawn and Garden Technician


What causes grass buildup?

Sometimes things are hectic, and it is easy to extend the time between each mowing session. Or other days you have time now, but the grass is a little wet—that can’t make that much of a difference, can it? In both instances, your mowing practices will cause grass buildup in the mower deck.

A good practice when mowing is to cut off the top third of the height. If you are trying to cut more than that or don’t adjust your mower deck for taller grass, you are going to accumulate more cuttings.

Lawn mowers aren’t designed to routinely cut wet grass. Wet grass is heavier than dry grass, so the lawn mower can’t throw the wet grass out as far or have enough power to throw the clippings as far back into the bag. Wet grass clippings have a natural tendency to stick together easily. When this is combined with not being thrown out as far when cut, the clippings stick to the underside of the mower and can get caked on.


Why is grass buildup bad?

While grass buildup in your mower deck can affect the performance of the mower blades and compromise the look of your freshly cut lawn, it also leads to rust and corrosion of the underside of the mower deck. With the increased grass buildup, there is naturally going to be more moisture in constant contact with the metal deck unless it is cleaned. The consistent moisture speeds up the development of rust and corrosion.


How to clean a mower deck

Cleaning your mower deck is going to take some time and effort, especially if you let the grass build up and get caked on. However, it is possible to clean up the grass buildup with a little work. Cleaning the deck should be done at least twice a year or more often if required. Below are some tips for cleaning your mower deck:

1. On walk behind mowers, ALWAYS empty the gas tank and make sure that you disconnect the spark plug before working near the mower deck. On riding mowers, it is not necessary to empty the gas tank, but ALWAYS remove the key prior to removing the mower deck.

2. On a flat surface, tip the walk behind mower on its side with the air filter facing up. This will expose the mower deck. For a riding mower or zero turn mower, either remove the deck completely or raise the deck high enough and safely secure it.

3. With a long-handled scraper or putty knife remove and properly discard the large chunks of caked on debris. (Use caution when working around the mower blade). With a garden hose and spray nozzle, or a high-pressure washer if available, soak any remaining debris and let set for a while. After the remaining debris has had a chance to soak, use the "jet” setting of the spray nozzle to remove any remaining debris. Any stubborn material can be removed with a stiff scrub brush.

4. Allow deck to air dry before use.


Household items

It doesn’t take a bunch of expensive products in order to clean up your grass buildup. You likely already have some of these common household items to help you get the job done.

Using the garden hose to spray off the grass buildup will easily remove the buildup that isn’t solidified. Once you have the loose clippings out of the way, you can work on removing the caked-on buildup with a scraper or putty knife.


Mower deck sprays

Mower deck sprays help make cleaning your grass buildup easier. By spraying your mower deck with a mower spray, the grass clippings don’t stick as easily. When you go to clean up any grass buildup after you’ve used a mower deck spray, you will notice it’s easy to hose off the underside of the mower deck and consider the job done! Make sure that after you’ve hosed off the mower deck to clean it, you allow it to dry completely before spraying again.


How to avoid grass buildup from happening again

Avoiding grass buildup doesn’t have to be a labor intensive, time-consuming task. With a few simple tricks, you can know you’ve done your part to help prevent grass buildup in your mower deck.


Applying mower deck coating

Mower deck coatings are a good preventative measure to take. By applying a simple spray lubricant, you can help prevent the grass clippings from sticking to the underside of your mower deck. The lubricant can be as simple as spray on vegetable oil!

Along with this, the lubricant will also make it easier to clean the underside of your mower deck, as well as prevent it from rusting. A key factor in applying a lubricant is making sure the deck is completely dry before spraying it on.


Wait for grass to dry

A very simple and easy way to ensure grass buildup doesn’t happen in your mower deck is to always mow when your grass is completely dry. Dry grass will not clump and stick together. When you mow your lawn while the grass is wet, it clumps up and usually stays on the top and sides of the inside of the mower deck.


Where can I get my lawn mower serviced?

Is your lawn mower in need of service beyond a simple mower deck cleaning? The team at Koenig Equipment has seen it all. Schedule a service appointment with our expert technicians so your equipment is prepared for the next cut.


Schedule Service Online