Should I Bag My Grass Clippings If I Have Weeds?

should i bag my grass clippings if have weeds

You should bag grass clippings if you have weeds, especially if there are seed heads growing. Although leaving grass clippings on the lawn, also known as mulching, is important for maintaining a healthy lawn, it has the opposite effect when there are weeds.

So, how do you find a balance between providing your lawn with the nutrients that it gets from grass clippings and preventing weeds from growing?

The answer is more complicated than simply stating whether you should or shouldn’t bag your grass clippings. It depends on the type of weeds, how often you mow your lawn and the season.

Find out all you need to know about the relationship between bagging grass clippings versus mulching in how to keep your lawn free from weeds.

What Does Bagging Grass Clippings Mean?

Bagging grass clippings means collecting the cut off leaves and disposing of them elsewhere. Basically, you are removing the grass that you mowed off from the lawn.

If you don’t have a lawn mower that also bags, bagging grass clippings becomes a time-consuming task. In that case, you need a lawn sweeper for collecting all the clippings.

Why You Should Bag Grass Clippings

Bagging grass clippings leaves your lawn neat and tidy. Mowing a lawn often also means seeing small lumps of grass spread around and bagging is the solution to this messy look.

Bagging also prevents rot. Rot occurs when there is too much clippings on the lawn and the grass underneath can no longer grow.

Generally, rot only occurs when the lawn is not mowed frequently enough. Mowing your lawn more frequently means the clippings are shorter which also makes it easier for the grass underneath to continue growing.

One of the advantages of bagging grass clippings is that you can compost it and then use it as fertilizer. You can also spread some of the clipping among flower beds to give them a nutrient boost.

What Is Mulching?

The alternative to bagging grass clippings is mulching. When mulching, grass clippings are left on the lawn to decompose.

Mulching clippings provides the soil, and so also the grass, with extra nutrients. Decomposing grass clippings have many of the same nutrients that are also found in common fertilizers such as nitrogen, potassium and phosphorus.

The problem with mulching is that grass is not the only thing that will grow. More fertile soil also makes it a prime location for weeds. If there is fungus somewhere on the lawn mulching would also help spread the fungus.

That is why it is better to bag grass clippings when there are weeds or fungus on the lawn. This helps prevent the further growth of fungus and weeds and makes it easier to remove the weeds.

Bagging Grass Clippings vs. Mulching

There are advantages and disadvantages to both bagging grass clippings and mulching. The key is to find a balance between both methods to keep your lawn healthy and free of weeds.


Bagging Pros
  • Prevents rot
  • Helps prevent the spread of fungus
  • Leaves lawn tidier
Bagging Cons
  • More work if lawn mower doesn’t bag
  • Takes away extra nutrients


Mulching Pros
  • Adds extra phosphorus, nitrogen and potassium to soil
  • Less work than bagging
Mulching Cons
  • Requires more frequent lawn mowing
  • Potentially spreads fungus
  • Causes rot if cut leaves are not short enough

Some people may choose to mulch in the winter and bag grass clippings in the summer. This is because there are more weeds growing in the warmer seasons.

You can also make the choice between bagging and mulching depending on how often you mow the lawn. As long as you mow the lawn frequently enough, the grass clippings shouldn’t cause rot and you’ll be preventing the growth of weeds, too.

Frequently Asked Questions:

Do Grass Clippings Cause Weeds?

Grass clippings do not cause weeds but they may make the problem worse. When you are mowing a lawn full of weeds, the seeds of the weeds may spread. So, you may see more weeds growing after mowing, regardless of whether you are bagging or mulching.

The solution is to remove weeds with seed heads, first. Better yet, completely remove the weeds before you mow the lawn.

How Long Does It Take Grass Clippings to Decompose?

Grass clippings decompose within weeks. The shorter the clippings, the faster it decomposes.

Ideally, you are mowing the lawn at a height that only removes the top 1/3 of the grass leaves. This ensures short enough clippings and keeps the grass that is still rooted healthy. The top 1/3 of grass is not much length so this does mean you have to mow the lawn more frequently.

Will Cutting Grass Short Kill Weeds?

Cutting grass short does not kill weeds but it does help prevent weeds from spreading on the lawn. Weeds spread the fastest once they are flowering or have seed heads.

Once weeds have reached this stage, mowing the lawn is not a good idea because you are helping to spread the seeds. You have to remove the weeds carefully before you can mow again.

The less intensive alternative is mowing your lawn more frequently. When you are keeping your grass short you are also keeping the weeds short. In other words, you are cutting off the weeds before they get to the flowering and seed heads stage.

weeds in lawn

The most important thing to consider when deciding between bagging grass clippings and mulching is the presence of weeds. If you already have weeds that are flowering or have seed heads it is better to bag your grass clippings because this prevents the seeds from spreading.

However, there is a chance that the seeds will spread anyway so the safest option is removing the weeds before you start mowing the lawn. Protect yourself from this risk by mowing the lawn more frequently.

So, ask yourself about the potential for weeds when choosing between bagging and mulching.

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