Should You Leave Grass Clippings on Your Lawn?

Your lawn mower probably came with a grass catcher. And you’re probably thinking of using it. Why wouldn’t you? It came in the box, and as Chekhov would say about a good story, everything that comes into play should serve some purpose. Otherwise it shouldn’t be there.

But hold that grass catcher! Unless you’re going to be overseeding after the mow, in which case you’ll want to pick them up, there’s a lot of good that comes with leaving the grass clippings on your lawn – or “grasscyling” – instead.

Why Clippings Should Stay

  • Healthy Lawn. Who doesn’t want lush, green grass? A key ingredient to getting that is grass itself! Grass clippings contain a ton of yummy nutrients that will decompose into the soil and feed your grass. So let them sit on your lawn if you want a healthy, green carpet.
  • Free Fertilizer. Grass clippings are a good source of nitrogen, an important nutrient that your grass needs to grow. And what better way to get that than for free! Toss the grass catcher into the closet and start mulching! Mulching – rather than simply cutting – helps clippings decompose faster. Your lawn can absorb those nutrients in as little as one week.
    Sun Joe 24V-X2-17LM Mulching Lawn Mower
    The single most important thing you can do when it comes to caring for your lawn is to get a mulching mower so that you can cut, mulch, and help clippings decompose fast.
  • Divert Waste. The average homeowner cuts grass once or twice a week. That’s a lot of grass – bagged in single-use plastic or paper bags – potentially headed to the landfill. In fact, it’s said that grass makes up a huge percentage of yard waste. Imagine how much unnecessary damage it would cause if they were bagged and tossed away. It’s absolutely mad that we would even do this, given all the benefits of simply leaving the clippings on the lawn.
  • Saves Taxes. Thankfully, some cities have stopped collecting grass from the curb. Instead they’re telling residents to grasscycle. As a result, there’s more money in the public purse, which could be used for better purposes.
  • Less Work. If none of the reasons above make any sense to you for whatever reason, consider this: leaving clippings on your lawn means less work for you. You don’t have to put in the effort to bag grass when you grasscycle. You don’t have to spend the time to bag grass. Besides, you don’t have to purchase the bag to bag the grass. Effort, time, and money in your pocket. All you have to do is mow. And once you’re done mowing, you can immediately hit the patio with an ice cold drink!

Addressing Myths

Uncle Bob may have told you that leaving grass clippings on your lawn was a bad idea. He said that it would cause weeds. Or maybe it was your aunt Mary who told you that you shouldn’t grasscycle because it will cause thatch.

Do they have a cause for concern? Here are the most common misconceptions people have about leaving grass clippings on the lawn.

Myth #1: Grass Clippings Cause Weeds

This is perhaps the most common misconception. Cutting a lawn that’s bound to have weeds, and then letting them germinate by leaving the clippings there. Sounds like a terrible idea doesn’t it?

Well, not exactly. It doesn’t make a difference whether you mow with or without a bag. That’s because weed seeds are dispersed as soon as the blade hits the grass. If you’re concerned about weeds, what you want to do instead is create a healthy lawn that will crowd out weed. How? By leaving the grass clippings on your lawn!

Myth #2: Grass Clippings Cause Thatch

Thatch is a beneficial layer of organic matter that occurs naturally between the grass plant and the soil. It acts as insulation for your lawn. But it can be a problem if there’s too much thatch, as it doesn’t allow water and fertilizer to penetrate or air to flow through.

Because grass clippings are considered organic matter, many people believe that they would be building excess thatch by leaving the clippings on the lawn. But the truth is that grass clippings get broken down by soil microorganisms. So they do not contribute to thatch.

Myth #3: Grass Clippings Spontaneously Combust

Given the right conditions, we absolutely do think it’s possible that grass clippings can spontaneously combust. Remember the time when the 8-year-old you tried to light your parent’s lawn with a magnifying glass? Given enough heat, anything can catch fire.

That said, rather than grass clippings laid out on the lawn, it’s way more likely that a huge pile of grass (think bagged grass going to the landfill) or a lawn mower bag full of grass stored in a garage will spontaneously combust. The reason is that so much heat is allowed to accumulate and there’s little to no air circulation. The bigger the pile, the hotter it can get, and the more likely it will spontaneously combust.

Myth #4: Grass Clippings Do Not Decompose Fast

We understand. Nobody wants to stare at a lawn full of grass clippings. It looks messy to say the least. But as long as you use a mulching mower – which cuts grass several times before dispersing it on the lawn – and abide by the “one-third rule” – which means to cut no more than a third of the leaf blade at once – that grass will disappear into the soil before you know it.

If you don’t own a mulching mower, you have all the more reason to cut high. It will keep your grass healthy and your clippings will decompose faster. If you don’t have the budget for a mulching mower, you can try to find a mulching blade and cover for your specific lawn mower.

Myth #5: Grass Clippings Kill Trees

We were pretty surprised to hear that some people worry their grass clippings will kill trees. Then we realized where this concern comes from. It isn’t so much the grass clippings that you have to worry about, but the products that you used on your lawn.

For instance, synthetic weed killers that you use on your grass can remain on the clippings, and when you use the clippings as mulch around trees and other plants, it can harm them. That’s like adding herbicide directly onto your trees and plants.

The best thing to do is to never use synthetic products on your lawn. We suggest following an organic yet effective approach to avoid the many problems that come with using synthetic lawn care products.

Cover the Whole Nine Yards

There’s absolutely nothing good that comes out of bagging and dumping grass clippings. But there’s a whole lot of good that comes from grasscycling. If you really want to toss something out, pick your grass catcher!

Have Fun Out There!