Mold and grass buildup on mower deck underside

[WinterDeere]

Yes, mulching decks are almost always worse than standard side-discharge decks, when it comes to clogging with grass.

But I mow wet and damp grass every few days for months at a time, since those are our local conditions, and never have an issue with clogging. If you do, I suspect you’re letting the grass get too long between mowings, which both gives it more opportunity for interlocking “structure”, and also might be bogging your deck speed down too far for it to properly eject.

Wet grass will stick in every possible inaccessible corner of your mower deck, but should never interfere with the deck’s ability to operate, at least in my experience. That wet gunk will dry into plaster between mowings, and then fall out making a mess and a racket when you hit a hard bump next week.

 

[DHD]

I use to own Wheel Horse garden tractors with belly mowers and had the same grass clipping build up and mold. It was difficult to clean out the built up clippings with the deck attached and a hassle to remove and reinstall the deck after each mowing just to rid the deck of clipping build up.

I now own riding mowers with front mount, flip up mowing decks and clean out built up grass clippings after each mowing session. (Husqvarna R322T AWD) It takes about 15 seconds to flip up the deck, to have easy access to clean out those grass clipping. It's also much easier and quicker to change out mower blades.

 

[walnutman]

Age old problem. One thing I got away from years ago is bagging. I get it with a small lawn that's manicured. Had a neighbor when I lived in SE PA that bagged his 1/2 acre and dumped it in a pile in the woods on MY property LOL. Over the years that pile got huge.
Also don't mind dandelions. To me they are edible, great for bees and are really just wildflowers.
I run a Ferris 61" ZTR. Love the suspension on it. Sold an Exmark after a year to save my kidneys.
I have the HF mower lift. Works well but I do put jackstands under it for safety.
Grass grows like crazy here in East Texas and rains are unpredictable. I just try to get it cut before the rain.
I mow about 3-1/2 acres once a week.
Clean the deck with a putty knife prob every two or three cuts.

 

[POGuy]

I try my best to only cut dry grass, but even dry grass has a decent amount of moisture in it. Tried the deck wash part on deck, really didn't work. I found myself lifting and fast releasing so deck would hit ground hard to dislodge clumps with water running. Easier and cleaner to raise deck and scrape with putty knife.

Here in Louisiana we also have the added fun of crawfish chimneys which are about 3-4 inches in diameter with a 1 inch hole in the center and 3 to 8 inches tall, so in addition to waiting for wet grass to dry, sometimes you would have to wait for the chimneys to dry. Adds a lot of mud to the clippings under the deck. So much so, you can feel a significant increase in effort to raise the deck.

 

[Hermio]

I have a John Deere D140 with a bagger that I use for the first few mows of the season to prevent all the dandelion seed distribution. I know it's not ideal to mow wet grass, but sometimes that isn't an option, and the grass has to get done (even though it means stopping every few laps and unclogging the chute to the bags).

I went out to the garage yesterday after mowing the lawn and could smell the wet grass under the mower deck. I took it off and spent the next two hours with a putty knife and wire brush scraping the grass off. It varied in depth from almost a thin wax like coating, to about three inches in some spots.

I have scraped most of it off I do believe, but would like to do something to it to prevent this from becoming an every time I mow thing. And yes, I will attempt to get the lawn mowed late afternoon, early evening when it is at its driest, but again, not always an option, and I will be ordering some new high lift blades to hopefully help with moving the cut grass across the deck and up the shoot.

Not sure if I will have to remove the blades and then pulleys to do a proper sanding, priming and painting/treating, or if there is some magic trick I can just apply now?

Thanks in advance folks.

I have had good luck with an under deck spray applied annually. I do not remember the name of the product.

 

[POGuy]

And what bad happens if leaving the crud in place? On my mowers it tends to eventually fall off by itself.

Loss of lift from blades.

 

[Jd1a]

My mower deck would clog, build up every time. Replaced the hi lift blades with regular blades. No more problems.

 

[JVR5333]

I have a John Deere D140 with a bagger that I use for the first few mows of the season to prevent all the dandelion seed distribution. I know it's not ideal to mow wet grass, but sometimes that isn't an option, and the grass has to get done (even though it means stopping every few laps and unclogging the chute to the bags).

I went out to the garage yesterday after mowing the lawn and could smell the wet grass under the mower deck. I took it off and spent the next two hours with a putty knife and wire brush scraping the grass off. It varied in depth from almost a thin wax like coating, to about three inches in some spots.

I have scraped most of it off I do believe, but would like to do something to it to prevent this from becoming an every time I mow thing. And yes, I will attempt to get the lawn mowed late afternoon, early evening when it is at its driest, but again, not always an option, and I will be ordering some new high lift blades to hopefully help with moving the cut grass across the deck and up the shoot.

Not sure if I will have to remove the blades and then pulleys to do a proper sanding, priming and painting/treating, or if there is some magic trick I can just apply now?

Thanks in advance folks.

Hey Bronco - I wish I could give you good news, but alas there is nothing quick and dirty (pun intended) here. I mow 30-acres of horse pastures - sometimes I get caught in rain with wet grass too. I mow the fescue very high - 5-1/2 to 6" in the grazing pastures, but even then grass and horse manure collects on the underside of the deck. I have to sharpen the 3 Skag blades about every 20hrs or less of mowing - I scrape underneath with a large putty knife every time I remove the blades - just part of the maintenance regime. Happy mowing my friend!

 

[cmjohn]

Sounds like someone has too much time on their hands

 

[JVR5333]

My mower deck would clog, build up every time. Replaced the hi lift blades with regular blades. No more problems.

I looked into hi-lift blades for my Skag 61" Turf-Tiger II zero turn machine, but after research and asking around - discovered that these blades greatly reduce the hp/rotation speed as they add a great deal of drag. Since I mow tall and thick pasture grass - I have to stick with the standard medium lift blades and keep them sharp. I rotate 3 different sets and have the "Yellow Hornet" blade sharpener - works awesome!