The Million Dollar Question: Lawnmower Mulching, Bagging, or Side Discharging?

Ok, maybe it is not for a million dollars, but you want your lawn to look like a million bucks, right? Let us walk through the benefits and disadvantages of lawnmower mulching, bagging, or side discharge of your grass clippings. It helps by thinking of your lawn by the old adages of putting food in our mouths – your lawn will become what it consumes.
Throughout this article, we will reference these 3 questions for each approach, so keep this in mind:
- Does your lawn have a lot of weeds?
- Does your lawn have more than half an inch of thatch?
- Are you cutting more than one-third the height of your grass?

When to Use Lawnmower Mulching
Now that the mechanics of mulching are out of the way, let us move on to the three questions as they pertain to lawnmower mulching.
- Weeds – Remember your lawn will become what it consumes. If you have a lot of weeds, mulching is not the best option. While some of the finer pieces will become beneficial organic matter, a lot of what goes back into the soil will come back like weeds.
- Thatch – If you have more than a half an inch of thatch in your lawn, mulching may help this breakdown. Thatch is the layer of dead roots and rhizomes that form a layer between your soil and new chutes of grass. A fine layer of freshly mown clippings benefits the decomposition of the thatch.
- Are you cutting more than 1/3 of the height off your grass? If so, mulching will likely require more than one pass to provide the fine clippings desired for decomposition. Additionally, if your lawn is relatively thick, cutting too much off at once can bog your mower down.

When Lawnmower Bagging is the Best Option
To determine if lawnmower bagging is the best option for your lawn, let us turn to our three questions:
- Weeds – Bagging is a great way to mow areas with weeds, which helps remove the unwanted sprigs and seeds that can start additional patches of weeds.
- Thatch – If you have thatch buildup, you can use a pull behind rake to lightly dethatch your lawn, then use your lawnmower bagging system to collect the excess thatch.
- Cutting more than 1/3 of the height of your grass. – Bagging will get the job done, but you will not only stop more frequently to empty your bagger, but you could also shock your lawn by exposing the roots that have been protected from the taller grass. So don’t cut too much!
NOTE: Dethatching is recommended in the early fall for cool-season grasses and in the early summer for warm-season grasses. When performing out of season, a pull behind rake with no added weight can do a nice job without a lot of damage.

When to Side Discharge With Your Lawnmower
Side discharging with your lawnmower is the way lawnmowers were designed to function. And for the environmentally conscious, the natural fertilizer of side discharged grass clipping should be your preferred method. It is more fuel-efficient to discharge clippings, and you will likely see a better cut in less time.
As with the other options, let’s revisit the 3 questions to learn when to side discharge:
- Weeds – This one is obvious to you by now, you will be potentially spreading the weed sprigs and seeds around. In this case, certain weeds will likely sprout elsewhere in your lawn.
- Thatch – Discharging is similar to mulching, except for clipping size. The larger clippings will take longer to decompose than mulched but will not hurt your lawn unless the next step is not followed.
- Cutting more than 1/3 of the grass height will always cause more problems than would help, and this is also the case with side discharge mowing.
NOTE: As a rule of thumb, you should NEVER have grass visibly lay on top of your lawn. First, this looks like a hayfield not a lawn! Second, this contributes to lawn disease that causes bare spots or worse.
The Holy Grail: The Combination Approach to Lawn Maintenance
There are definite pros and cons to mulching, bagging, or discharging your grass clippings. All three are effective, but a combination approach should be something to consider. Try this out:
- First Mow of the Year – Bag It! Lawnmower bagging will clean up the dead leaves and debris that have come down in the winter.
- Spring Mowing – Mulch It! Grass mulching in the Spring (if you keep the three questions in mind) can help make your lawn thicker and help inhibit weed growth.
- Summer Mowing – Discharge It! Following the three questions at the beginning of the year makes this option easier to accomplish. If you are not cutting off more than a third of your grass, the clippings will help provide nutrients to your now thick lawn.
- Early Fall – Dethatch It! We added this in because control of thatch is crucial to a healthy lawn.
- Fall – Mulch It, THEN Bag It! Unless you have an abundance of leaves, mulching them is a great way to add some nutrients before winter. On your last one or two mowings of the season, bagging up the debris will give your lawn a healthy start for the long winter ahead.