Mold and grass buildup on mower deck underside

   / Mold and grass buildup on mower deck underside #61  
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.
Best laugh I've had since the snow melted away.

I live on a small farm, with over 50 acres of hay. Sometime around mid-May, those hay fields are covered with dandelions, and a few days later the seeds are disbursed as nature intended. A waste of time and money to try to stop it, as by the time the hay is ready to cut the dandelions are gone.

I have learned over my 75 years that fighting with dandelions in my lawn is a futile endeavor. I have learned to appreciate the beauty of the yellow mixed with the green (John Deere colors!) when they are in bloom, and to live with the seed heads later. Life is too short to fight battles you know you can't win.
 
   / Mold and grass buildup on mower deck underside #63  
Dandelions are easy. I have some direct neighbors that look like they must be growing the things to harvest, but not a single dandelion in my yard. Getting rid of them is easy:

Year 1: Spray SURGE in the fall, a 3-point boom sprayer works best.
Year 2 early spring: Apply a pre-emergent weed block with your first round of fertilizer, before the grass comes out of winter dormancy.
Year 2 late spring: Spray Escalade II to kill any dandelions or other broadleaf weeds that weren't killed in the fall spraying.

Thereafter, your early spring pre-emergent application will keep them at bay, there should be no need for yearly spraying. The few that come up can be hit with a hand sprayer, there won't be more than a few per acre.
 
   / Mold and grass buildup on mower deck underside #64  
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.
That pile of grass clippings would make great mulch/compost for a vegetable garden. And as for the dandelions, if the price of coffee keeps rising, we'll need them for this:
 
   / Mold and grass buildup on mower deck underside #65  
My $.02.
I have found after decades of lawn mowing that not all decks are created equal. I had two tractors, (lawn and garden), of the same brand. The garden tractor with a 54" deck would clog with a little dew on the grass, or even if the grass was too tall. The lawn tractor would mow tall grass in standing water and never clog. IMO, some design engineers actually calculate airflow when designing a new deck, others do not.
 
   / Mold and grass buildup on mower deck underside #66  
My $.02.
I have found after decades of lawn mowing that not all decks are created equal. I had two tractors, (lawn and garden), of the same brand. The garden tractor with a 54" deck would clog with a little dew on the grass, or even if the grass was too tall. The lawn tractor would mow tall grass in standing water and never clog. IMO, some design engineers actually calculate airflow when designing a new deck, others do not.
Very true indeed!
 
   / Mold and grass buildup on mower deck underside #67  
I am going to try Fluid Film on the underside of the deck. I think it could make a difference in the grass buildup. Has anyone of you tried it.
 
   / Mold and grass buildup on mower deck underside #68  
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 a 2014 troybilt that the deck is slowly rusting away. I scrapped it after every mow wet or dry to ensure most was removed. I found my scrapper was worse then the grass. I have a new Deere and I only use wood spatulas to clean the deck. The Deere does my yard, the Bilt my field until the Bilt dies.
 
   / Mold and grass buildup on mower deck underside #69  
I'm asked all the time how to keep the deck clean underneath. Most of these folks are intimidated by removing the deck and don't have a lift. Some the best they can do is scrape out through the chute when they deal with nice, healthy May grass. Even that keeps the deck cleaner as it helps the grass keep moving out. Some ask because I gave them the wag of a finger for either pressure washing and packing grass around their transmissions or not dealing with the bushel of grass on top their deck. Or washing the top of the deck, which as a regular practice- isn't good either.

Something to consider for those simply discharging the clippings are low lift blades. Less aggregate to wear the blades, less packing under the deck.

Those rounded scrapers are great tools. Flexible thin ones are available, but nice sturdy home made ones from heavy paint scrapers are the bomb. Oscillating tools are an outstanding tool for dried stuck on grass.
 
   / Mold and grass buildup on mower deck underside #70  
I am going to try Fluid Film on the underside of the deck. I think it could make a difference in the grass buildup. Has anyone of you tried it.
It's I think a good thing to do for long term care anyways. When you have the deck cleaned and ready for storage is when I do it. Helps with sticking?
 
   / Mold and grass buildup on mower deck underside #71  
Mowing dry buildup never a problem.

I have motors outlasted steel decks.

My best combo is aluminum deck but then I replace worn out wheels every 15 to 20 years.

No experience with composite deck.
 
   / Mold and grass buildup on mower deck underside #72  
Loss of lift from blades.
Hmm. So when the crud builds up on the sides, to me that's a bit like a better fitting fan shroud on a radiator.

But you're saying it leads to less lift. How come? (I've obviously never spent time thinking about this, or much about mowers in general).
 
   / Mold and grass buildup on mower deck underside #73  
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 spray my 60 in deck on my kabota and also 48 in fabricated deck on Cub cadet with fluid film quite generously and when I take off in the fall I have almost no mold or grass on it at all before I started doing that I was scraping stuff off all the time so it works great for me , I know people will say waste of time but I assure you it works extremely well
 
   / Mold and grass buildup on mower deck underside #74  
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.
Shortest distance between two points is a straight line. Simplicity.
Following each mowing session I merely take a garden hose fitted with a variable spray nozzle and shoot water at high pressure at deck underside. Means bending a few minutes to hit all surfaces from both sides of tractor model GR2110. Because I cannot see the surfaces I visualize from memory the underside configuration. Freshly cut grass falls off in clumps.

Kubota decks are magnesium, I believe. So, rust is not an issue or observed in past ten years of ownership. Blade spindles are mounted on cup-like hubs to hold lots of grease that, I assume, is fed as hub gets warmer during run. Water will not displace grease in enclosed grease cup; water-RESISTANT, not water-PROOF.

Come time to switch-over to snow-blowing (Northeast), deck scraping is minimal.
 
   / Mold and grass buildup on mower deck underside #75  
Unfortunately, nothing is close to permanent. There are products such as MoDeck for that purpose. I've seen those who wax the underside of a new deck to the guy who used bedliner. I've personally tried grease paint on a brand new and prepped deck. The dirt fines picked up by the blades are an effective sand blaster. I have customers who park on a mower lift and scrape it each time.
How about a few coats of an epoxy paint such as POR-15? Glossy (slippery) and hard as nails.
 
   / Mold and grass buildup on mower deck underside #76  
But you're saying it leads to less lift. How come? (I've obviously never spent time thinking about this, or much about mowers in general).
I'll take a stab at it and say, IMHO, it is because to get the lift you need a certain quantity of air to move in a specific direction. Built-up grass reduces the volume available and messes with the path of airflow. Also creates friction in the airflow, slowing things down. Just my layman's guess...
I spray my 60 in deck on my kabota and also 48 in fabricated deck on Cub cadet with fluid film quite generously and when I take off in the fall I have almost no mold or grass on it at all before I started doing that I was scraping stuff off all the time so it works great for me , I know people will say waste of time but I assure you it works extremely well
I will have to say that the 54" deck on my CC ZTXS5 54 does stay remarkably clean. I only notice build-up in a couple of areas: a little bit right around the holes where the spindles enter the deck, a little at the rear corner of the discharge chute and one other corner inside the deck (I think it is a corner behind the middle blade. Otherwise, bare steel in there.
 
   / Mold and grass buildup on mower deck underside #77  
Kubota does not and never will make a deck from magnesum or magnesum alloy. Way to expensive to even consider doing. They are for the most part, fabricated steel. No manufacturer would ever build a deck from magnesum alloy in as much as it cannot be fabricated, it has to be pressure die cast. Far as water contimantion of the spindle bearings when power washing the underside of ANY deck, they will all suffer from that water contaimation of the bearings. Why you shoud regrease them after doing that deed and for those that have sealed spindles (no grease fittings) it only hastens the spindle bearings demise.

Much better to manually clean off the cud versus using pressureized water to clean it.

Don't say I didn't warn you...lol
 
   / Mold and grass buildup on mower deck underside #78  
I drive my scut up onto car ramps after each use and use a garden hose to spray off grass which I then put in my compost.
 
   / Mold and grass buildup on mower deck underside #79  
I'll take a stab at it and say, IMHO, it is because to get the lift you need a certain quantity of air to move in a specific direction. Built-up grass reduces the volume available and messes with the path of airflow. Also creates friction in the airflow, slowing things down. Just my layman's guess...
Sticking with my radiator shroud comparison, the volume would be coming from below the blades just like from the front of a vehicle's radiator.

And to maximize the effectiveness of the fan, the shroud should fit a tightly as possible relative to the fan.

Of course, then the air then has to go somewhere, and on my "single prop" 6-footer it exits left, judging by where the cut grass ends up.
 
   / Mold and grass buildup on mower deck underside #80  
I just finished scraping all the moldy crap out from under the deck on my S240 and sharpening the blades. I blew the mower off with electric blower and the storage compartment door on the right fender flew open revealing a nice sized red wasp nest. I switch the blower to high and never saw them or their nest again and they didn’t show up later. We have had rain after rain after rain the last two months and the ground is saturated. I serviced my zero turn yesterday and it had mow muffins caked up under it badly too. It’s 81,sunny and humid now. I think I’ll mow some later this afternoon. The ground is too soft to use the small tractor and finishing mower.
 

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