Is using a mulcher mower exclusively bad for the lawn, in the long run?

Question

When using a high quality mulcher exclusively to cut the grass, are there any long term negative effects that need to be considered? I am not looking for a high end, perfect lawn; it should be passably good-looking and the grass should not be killed off and replaced by unwanted things like moss or weeds (at least not faster than when using a regular mower and disposing the cut grass). At the current stage in my life the lawn serves no particular purpose aside from existing, i.e., it does not need to survive playing children or big animals digging around.

My thinking "pro" mulcher is that aside from saving time and effort getting rid, or composting the cut grass, I would also let nature recycle the cuts naturally, and I would probably have to use less fertilizer – again saving time and effort, and possibly also being a good thing in itself.

Answer 1

So long as you don't let the grass get overly tall, (and if you do, just raise the cutting height, then gradually reduce it over a few weeks) there's nothing wrong with always mulching.

If the grass gets absurdly tall, rake & compost that one cutting, then go back to mulching. If it never gets absurdly tall, just mulch.

If you get your mowing height up to 3" / 75mm or so, you'll get deeper and healthier roots (and more drought resistance) than with lower mowing heights, and the grass will shade out weeds better than with lower mowing heights.

Of course, if the lawn serves no purpose in your life, you might want to consider if the space is better used for some other purpose, such as a vegetable, herb, or flower garden.

Answer 2

On the contrary, mulching returns nutrients and water to the lawn. If you bag your clippings, you are simply increasing the need for fertilizer and perhaps watering. Mulching leaves is also beneficial as it creates food for earthworms. I've heard some myths about mulching causing thatch but that's completely backwards. Thatch is caused by roots growing the surface of the soil and is associated with chemical fertilizers.

The thing that's important is that the clippings get chopped up into fine pieces. I used to have a crappy electric mower which would bog down and leave clumps of grass on the lawn. Clumps like that will kill the lawn under them. I now have an awesome electric mower with a double blade for mulching. I can't even see the clippings if I search for them.

Cutting your lawn high and mulching will make the lawn healthier and save you time and effort in the long run.

Answer 3

In my experience there are two basic approaches to lawns. Both are valid:

1. Bag and compost your clippings. In this case, you are removing material from the soil, and so you should also fertilize your lawn to keep the soil healthy.
2. Mulch. In this case, you are not removing material from the soil, since the original clipping can return. You may still want other treatments, such as weed, pest, or fungal control, but if you have the right kind of grass for your climate and sun levels you likely won't need to fertilize.

In my experience option 1 tends to nicer looking grass, but option 2 can be overall just as healthy, and it's also a LOT less work.

I personally go mostly option 2, but I also like to leave my first cut of the spring for very late, and let things get kinda shaggy so the roots can get a good start. This means my first couple of cuts are kind of high and the first cut especially leaves a lot of clippings. The result is I need to bag that first cut of the spring.

There's also a point every summer where we're away for a couple weeks, and I usually forget to make lawn arrangements for while we're gone. The circumstances there mean it could be three or even four weeks from the last cut before we go until the first after we're back, and in this case I will also want to bag that one longer cut.

Because I do occasionally bag, I will also fertilize the soil... but only about every third of fourth year. Remember, nitrogen burn is also a thing and we don't want to over-fertilize.

Otherwise, there's one more thing to watch for when mulching: thatch lock. This is generally NOT a problem; a layer of thatch is actually good for your lawn and soil. It helps hold in moisture and block out weeds. But you can also have too much. Thatch lock is when the thatch has become too thick and starts to thin out your grass. In that case you may need to use a garden rake to pull some away. But if you keep up with things, you'll likely never experience this, and if you do it's usually because there's material coming in from somewhere else, as well.