I bet the biggest debate in the yard care world is “is it better to mulch my clippings or catch them in the bag?” In fact, in my years in the lawn care industry, I have had customers swear by one way or the other and they just would not listen to reason! 
Let me break this down for ya ok?
Why Mulch Clippings When You Cut
Mulching lawn mowers are ones that clip the grass blades and then grind, slice and cut the pieces into super fine bits before dropping them back into the lawn. This is a very good and “green” practice because you are literally recycling the clippings back into the yard. Remember, 90% of the grass blade is water and the rest is organic nutrients. When you mulch with a properly powered mulching mower, those small clippings dry and shrivel up withing hours and drop their precious nutrients right into the lawn.
A common misconception with mulching is that doing it over and over all year will contribute to a lawn thatch buildup. This is a complete fallacy as I mentioned above, the clipping shrivel almost immediately. Now I will tell you that many homeowners go wrong by trying to convert a non-mulching mower into a mulching mower, and this is asking for problems.
What I mean is they take a cheap, bagging mower and take the bag off and let the clippings fall as they may. Problem here is the mower does not have a mulching blade so clumps drop out! Those clumps will contribute to thatch and kill sections of the lawn! ouch!!!
Another big issue I have seen is that people buy underpowered mulching mowers. Even if you have a mulching lawn mower with a good mulching blade, if it does not pack enough RPMs the bits will fall out in clumps. I dunno why, but many companies make mulching mowers that are just not powerful enough for thicker lawns. I always recommend you get a mulching mower that is a minimum or 5 horse power. This will be enough!
Wait, there are more things to consider: Even if you have a good mulching mower with plenty of power, if the lawn mower deck is not deep enough, the clippings will still fall out too quickly and clump! You want a deep deck!
That’s a lot to consider, so what is the best mulching mower? Look.
Why Catch Grass Clippings
Now that I have hopefully convinced you to mulch, there are a few situations where it will be best to catch and the first one is if your lawn mower is not able to mulch correctly (like I already talked about above). If you can’t go buy a new mower, then just keep catching, but DO NOT try and convert your mower… it ain’t gonna work and it’s a safety hazard anyway!
When to Catch Grass Clippings
I do want you to catch the clippings when you notice a lawn fungus or disease present. If this happens, you want to suck up the clippings and get rid of them. No sense is spreading the spores around. In addition, you need to catch if you have let the lawn grow too tall between cuttings. This can happen if you go on vacation in May, for example, and the lawn overgrows. In this case, even the best mulching mower will leave clumps, so you should catch the stuff just to be safe.
I also recommend you catch at least every 3rd or 4th mowing and use the grass clippings as mulch around annual flowers in your garden. Grass clippings will do a nice job of holding in moisture around annuals. I don’t think grass is a good mulch for regular shrub beds, but it works well for annual flowers.
So what do you think? Wanna argue with me? Go ahead, I’m good with it… maybe you guys can give me some better tips?
{ 5 comments… read them below or add one }
I went with the mulching option on my new mower. The lawn had been managed by my neighbor and his company. They were always just trying to get it done as fast as possible. They didn’t mulch or bag. Lawn was completely trashed after 2 years of that. Its back under my control now. Heading in the right direction.
The mulching on my mower is incredible. it will turn grass into goo of you go slow enough.
I appreciate all the tips that are found within the pages of your site here. I have relied upon in heavily during my adventure into lawn care. Thanks dude.
Hello: My neighbor said that mulching the grass will spread weeds more than normal. His thinking is that the weed pollen (or whatever it’s called) gets spread all over the lawn when mulching. I have not been able to find anything thus far that supports what he said. Everything I’ve read about grass mulching has been pretty much all positive–no mention of excess weeds. Have you seen more weeds on mulched lawns, or is this not an issue? Thank you.
Hi Mel,
your neighbor is believing a myth. Weed seeds spread from the wind, not your lawn mower. Tell him to worry about his own lawn, LOL
AL
how about dollar weed and mulching?????
dollar weed is best controlled with cultural practices. Be sure to aerate in spring and fall and overseed. that will choke it out naturally.