Should I Bag My Grass Clippings If I Have Weeds

Should I Bag My Grass Clippings If I Have Weeds in My Lawn?

If you are like most people, then you put a lot of effort into having a beautiful green lawn, and maintaining one is difficult, especially if you have some weeds. If you maintain your lawn you should be mowing it regularly, this will then produce grass clippings, and the grass clippings will have to go somewhere. So you may be asking yourself Should I bag my grass clippings if I have weeds in my lawn?

Trust and Accuracy Information

This article was last updated on by Lawn Chick Owner Sarah Jameson
Article content reviewed for accuracy by Horticulturist Arthur Davidson, A.S.

You essentially have two options when dealing with grass clippings, and that is whether to bag them or mulch them. This can be a difficult decision which might be based on the time you have to put in, the money you want to spend to pay someone else to take care of it, or if you are struggling to improve your lawn and eliminate weeds.

For those who specifically have a weed problem, it is important to take a look at your lawn and make a few decisions to keep it looking healthy and in its best shape. is reader supported. If you make a purchase after clicking a link, I may earn a commission at no additional cost to you.

What is bagging?

Bagging your grass clippings is when you collect your cut grass and place them in a compost bin or approved yard waste container. You are essentially throwing your clippings away and disposing of them properly.

There are actually bagging mowers that can make bagging much easier than simply picking up the clippings and placing them into a bag manually.

Bagging Grass Clippings

If you don’t have a bagging mower, you can get a push lawn sweeper to sweep up the clippings on your lawn after you mow. It’s a pretty easy and inexpensive option (and sure beats a rake!).

Arthur Davidson, a horticulturist on our expert panel, suggests that composting weeds is a good option. “Composting should kill most weed seeds. However, Compost piles usually have cooler areas on the sides and top of the pile. Some use a secondary step to kill weed seeds in a translucent white plastic barrel. When the barrel is sealed heat builds up quickly in full sun. Of course you could spread out ‘finished compost’ and cover with clear plastic, solarizing the pile.”

Why bag clippings?

Many people believe that bagging creates better curb appeal due to the lack of visible grass clumps. This is one of the main reasons for bagging because mulch can actually be helpful to your lawn.

Bagging is also good for those who mow less often and have long grass clippings. This is mainly due to the fact that large clumps of grass can create rot and kill the growing grass beneath it.

But, Sarah, should I bag my grass clippings if I have weeds in my lawn?

The answer is maybe. Bagging grass clippings can help to prevent spreading annual weed seeds (like crabgrass) into your lawn, but if you mow frequently you may not need to (more on that in a moment).

What is mulching?

Mulching your grass clippings means that you keep them in your yard. They should decompose over time and become a layer on top of the surface of your lawn.

Why mulch clippings?

Mulching is thought to save a lot of time and energy because the mulch adds nutrients to your lawn such as nitrogen, phosphorus, and potassium. These nutrients are actually normally in fertilizer, and clippings can give you up to 30% of the number of nutrients your lawn needs to grow healthy and strong.

Other reasons for allowing mulch to accumulate would be to conserve the moisture in your soil, as well as improve the health and density of the area. Many people also like mulching because you will save money and avoid chemical nutrients. Additionally, you will save time since you do not have to go through the process of picking up your grass clippings, but rather leave them where they are after mowing.

When you should choose to mulch

In order to break down grass clippings, you will need high temperatures as well as humidity. This makes mulching lawn clippings is best while in the hottest months. Especially if you have time to cut your grass every four days or so, mulching can be a great option.

Another time you might want to mulch is if your lawn is thin and seems like it needs more nutrients. Mulching can naturally return nutrients to the soil and save plenty of money on fertilizers.

What about thatch build up?

When you decide to mulch you will have grass clippings on top of your lawn and the ones that do not break down become thatch. This blocks the flow of oxygen and nutrients to your lawn, which in turn makes your grass begin to thin out.

If you are concerned regarding thatch build-up, this should not be an issue if you follow two rules.

  1. Cut your lawn with the one-third rule so that they are small enough to decompose quickly
  2. Discharge your grass on the side you haven’t mowed yet, so the pieces will be cut smaller every time you go over them again.

There are also options to purchase a mower specifically for mulching, or adding a mulching attachment to your current mower if you are especially concerned.

Composting Grass Clippings is a Good Option if You Don't Mulch When You Mow
If you bag your grass clippings, consider composting them.

Fungus and lawn disease

If you happen to see any signs of fungus or law disease do not mulch your clippings, but instead bag them. If you do mulch your clippings this can spread the disease to the rest of your lawn.

Fungus can also occur within mulch in damp conditions when the bacteria begins to feed on your mulch. In this case, immediately begin to bag your lawn and only resume mulching when all fungus has cleared.

Eliminating weeds

If you’re trying to improve your lawn and eliminate weeds then you will need to take a look at what type of weed is growing to decide whether to bag or mulch.

Identify Your Weeds

First, you will want to ask yourself if the grass-like weeds growing is an annual weed. Using crabgrass as an example weed, it is important to understand that this weed self seeds itself. Crabgrass also only grows in heat. If you cut your lawn regularly then you will not be allowing the weeds to grow large enough to actually form any seed heads. In this case, you would be able to mulch your lawn.

First, you will need to understand what a crabgrass seed head looks like, or the specific type of weed seed head you are looking at. If you happen to see the seed head then pull them out and dispose of the seed heads before bagging. If you do not see any seed heads you can instead continue with mulching.

Should I Bag my Grass Clippings if I Have Weeds in My Lawn?

For weeds that you cannot necessarily see a seed head, you should take other measures and pull them. If you feel you are able to pull out all of the weeds, then there is no problem with mulching the rest of your lawn. If you are unable to contain the number of weeds in your lawn, then you should decide to bag.

When in a situation where the weeds keep growing, you will need to make a decision depending on how often you are able to cut your lawn. If you are not in a position to cut your lawn every 4-5 days in the summer months when the weeds are growing, then you should choose to bag instead. This is due to the fact that cutting any more often is not recommended in summer, and letting grass grow taller would allow them to grow seed heads.

So, Should I Bag My Grass Clippings if I have Weeds in My Lawn?

Economically, it makes sense to mulch year-round for incredibly large areas of grass such as parks or fields. Generally, in residential areas, large amounts of grass clippings can become problematic. They can stick to your body or feet, be tracked into the house and stain clothes as well.

So, should I bag my grass clippings if I have weeds or not?

Unless you have the time to bag your clippings yourself or want to pay someone to do it for you, generally you should be mulching in the summer, and bagging in the winter.

In the case of having weeds, then you should only mulch if you are able to pull all the weeds out, or at least the seed heads. It is important to note that it can often be very difficult to remove all the seeds.

If you decide to mulch and there will be seeds left behind, it will spread the weed seeds around to completely disperse them across your lawn. This will create a much larger infestation than you had before and might ruin your lawn. To be safe, choose to mulch only when your lawn is completely rid of weeds, and if you must mulch, mow more frequently so your lawn weeds never have time to develop seed heads.

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Sarah Jameson’s blog, Lawn Chick, is read by over 2 million homeowners each year and she is regularly cited as an expert source of lawn care knowledge by major publications. Her goal is to meet you where you are, and help you achieve a yard you’ll be proud of. Ready to take the next step toward improving your lawn? Grab her free lawn care cheat-sheet: What to Do When - Take the Guesswork Out of Lawn Care, or upgrade your garage by browsing her favorite DIY lawn care products.

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