That's close to the way my mulching mower works. The main difference is that mine has a metal plate that can be attached to cover the vent and keep the grass in.

Mulch plugs, which can be purchased for lawn tractor mower decks, do essentially the same thing. You may experience some grass clumping depending on your deck configuration. I think it's worth trying.

-Deerslayer

Cool, I will try tomorrow! :)

Sounds like no sidewalk cleanup to me.
The vent is really to blow/throw the clippings into the bag.
No bag / no vent

Mine has 2 vents. One back vent for the bag and another hole for the side vent(the one with color black cover on the left part of the picture). Both have cover for the vents.

When I mow at my back, close to the house, I bag it since it's still infected with powdery mildew. But it's improving. Maybe, the milk I applied help. Today, I applied baking soda. Anyways, my mower pic is below.

{{gwi:96947}}

If you cover both discharge holes, you'll have a mulching mower. It looks like your mower was designed to easily change between side discharge, rear bagging, and mulch mowing.

-Deerslayer

I didn't know that my mower was capable of mulch mowing. I have always used side discharge. And I thought that it was the proper way of doing it. Where/when do we do/use side discharge?

Huh??? you have a big sticker on the front that says "mulcher." Kinda hard to miss.

It's because, I really never paid attention to lawn care before. I just turn it on then walk. Hahaha. It was only last night that I saw the mulcher string in front. LOL. It's been with me since 2003.

I "mulch" with side discharge by always mowing in patterns that lead me to run over the clippings...

Hey folks, I tried it yesterday in my front lawn and my mower did a great job. I was expecting for something similar to what I saw in my neighbor. I saw the path of his mower with dried blades on top of the lawn. I didn't see those in mine. The blades were cutted so fine. I should have done this before. I only learned recently that grass clippings gives shade and does give nitrogen too.

For my affected lawn with powdery mildew, I did bag them. However, 95% of powdery mildew is gone which is a good news.

Especially in the spring where conditions are a little wet, I side discharge like weigojmi. The grass clippings on the surface are gone in no time and no clumps!

"Where/when do we use side discharge?"

When your grass is too tall or too wet to mulch mow (because it clumps) and you don't want to bag. If you mow when your grass is dry and don't cut more than 1/3 of its height, you don't need side discharge. Bag if your lawn has a disease, otherwise, mulch mow.

-Deerslayer

I have a Honda push mower. I always mulch, even when the lawn is wet. The clippings are 1/8 - 1/4" long and disappear in a day or two. Free fertilizer!

Strangely enough, I use the Robomower (I have few allergies, but I do react to the volatiles from cut grass). Besides, that's time I can spend maintaining/enlarging the gardens.

She (her name is Myrtle) has a triple chamber system that reduces the cut blades to shavings maybe a sixteenth of an inch long. They filter right down into the grass and disappear. It takes a bit until she learned the lawn and the lawn adjusted to her cross-patterning (she doesn't do stripes, but hits it from all eight major directions instead).

Once they learned each other, the lawn looks fantastic.