Mulching grass when you mow can risk spreading grass diseases from one area to another. It can also spread weed seeds, which can worsen a weed invasion. Additionally, mulching requires a powerful mower, which means you’ll need to spend more on a mower if you want to mulch. Mulching grass while mowing also requires the blade to cut the grass multiple times, which dulls the blade faster. So, your mower will need more maintenance if you use it for mulching. Finally, mulching grass takes longer than other forms of mowing, so it will increase the amount of time you spend on yard work.
5 Cons of Mulching Grass When You Mow
Mulching your grass clippings can have a lot of benefits, including returning key nutrients to the soil. However, mulching your grass does have drawbacks. Keep these negatives in mind when considering whether or not to mulch your grass.
It Can Spread Lawn Diseases
If your lawn has a fungal disease or lawn rust, mulching can spread the disease from one area to another. Mulching cuts the diseased grass into small pieces and spreads it across your yard. These bits of diseased grass in turn infect the healthy grass in your lawn.
- Fungal lawn diseases can be spread by mulching as you mow.
- The small pieces of diseased grass can make contact with healthy grass, which spreads the disease.
- If your lawn has a disease, bag the grass clippings when you mow and throw them out.
Keep on the lookout for patches of grass in your yard that are discolored or struggling—these could be signs of disease. If your lawn is suffering from a disease, such as dollar spot fungus, bag your grass clippings to inhibit the disease. Wait to mulch once your grass is healthy throughout the whole lawn.
It Can Cause More Weed Problems
Mowing weeds with a mulching mower can spread the weed seeds through your yard. Weed seeds are hardy and very unlikely to be destroyed by a mower blade. So, the grass clippings that drop back to your lawn surface after mulching will likely contain weed seeds.
- Using a mulching mower can distribute weed seeds across your yard.
- Weed seeds won’t be damaged by a mulching blade, and will sprout when they drop back to the soil.
- If your lawn has weeds with seed heads, use a bagger to collect the seeds with the grass clippings.
If you see fluffy dandelion heads and other weeds have gone to seed, bag your grass clippings. Then, you can throw out the clippings and weed seeds together. However, if the weed growth in your yard has not yet started to develop seed heads, you can safely mow with a mulching blade.
You’ll Need to Invest in Your Mower
Mulching your lawn with your mower requires more than simply installing a mulching blade on any mower. A mulching mower cuts each piece of grass several times to break it down into small pieces, all while still moving forward and cutting new grass. This requires a powerful motor.
- Mulching blades are only effective on powerful mowers.
- Using a mulching blade on an underpowered mower can cause it to cut your lawn poorly.
- You will need a gas-powered mower—most electric mowers aren’t strong enough to mulch grass.
Electric mowers are seldom capable of mulching, so you may have to invest in a more powerful gas mower. Plus, you’ll have to buy a specialized mulching blade, like this one. If you don’t want to invest in a new mower and blade, consider the benefits of mulching vs. side discharge for mowing.
Your Mower Blade Will Dull Faster
Using a mower to mulch requires your mower blade to cut each piece of grass several times. A regular mower blade only cuts each grass blade once. Because it has to make more cuts, mulching blades dull faster than standard mower blades. This means you’ll need to sharpen your mower blade more frequently.
- Mowing with a mulching blade causes your mower blade to go dull up to 3 times faster.
- You will need to sharpen your mower blade as often as once per month if you use a mulching blade.
- Mowing with a dull blade can shred and damage your grass.
Standard mower blades require sharpening 2 times per season—usually in spring and midsummer. A mulching blade will go dull 2 to 3 times faster. So, expect to sharpen your mower blade once per month if you prefer mulching your grass.
Lawn Work Will Take More Time
Mulching with a mower requires you to go more slowly than standard mowing. Pushing or driving the mower at regular speeds can lead to a messy cut. So, you’ll need to reduce your speed and take more time with your lawn care routine.
- Mulching while mowing requires you to mow more slowly.
- If you mow too quickly, the grass will not be cut evenly, which can require extra passes with the mower.
- After mulching, you will need to rake messy piles of grass clippings so they reach the soil.
Additionally, mulching mowers often leave messy piles of grass cuttings behind. To get rid of these, you’ll have to rake the grass clippings to spread them evenly throughout your yard. To reduce cleanup time, make sure to only mow dry grass. This can be avoided by making sure you don’t mow too early in the day.
Does Mulching Grass Hurt Your Lawn?
Mulching can cause harm to your lawn if your lawn is currently afflicted with a disease or a heavy weed infestation. Diseases and weed seeds can be spread by mulching the lawn clippings. However, using a sharp mulching blade will not damage or shred your grass blades as you mow.
- Mulching can cause harm to lawns afflicted with disease or weeds that have gone to seed.
- Specialized mulching mowers and blades do not harm grass as you mow.
- Mulching grass returns nutrients to the soil, since grass clippings decompose surprisingly fast.
Mulching while mowing can have a lot of benefits for a healthy lawn. Mulched grass clippings return organic matter to the soil, which acts as free fertilizer. Grass clippings decompose quickly, so you can give a struggling yard a bit more life by mulching as you mow.
Does Mulching Grass Cause Moss?
Mulching your grass does not cause moss to grow in your lawn. Instead, moss grows when grass is unhealthy. You can boost grass health by fertilizing your lawn, aerating the soil, dethatching, or improving the soil pH. When your grass is growing strong, it will easily choke out moss.
- Moss in your lawn is not caused by mulching as you mow.
- Moss grows where grass is struggling due to shade, too much moisture, or poor soil conditions.
- Boost your lawn’s health with fertilizer, aeration, and other improvements to drive out moss.
- Mulching your lawn can be a tool to help strengthen grass and eliminate moss.
Mulching your grass can actually be an effective weapon against moss. Grass clippings act as fertilizer and boost soil nutrients, which feeds grass roots. So, if your lawn is being invaded by moss, don’t quit mulching when you mow.
Are There Disadvantages to Mulching When You Mow?
Mulching your grass has its drawbacks. The most important ones to be aware of are:
- Mulched grass clippings can spread lawn diseases from one area to another.
- Weed seeds can be spread to new areas if you mulch your grass.
- You’ll need a powerful mower to mulch grass effectively—electric mowers are rarely strong enough.
- Mulching blades go dull faster, which means you’ll need to resharpen them often.
- Mulching as you mow requires you to mow more slowly, so your mowing routine will take longer.
Mulching grass clippings certainly has pluses as well, since grass clippings are an excellent source of soil nutrients. However, in some cases, it’s best to bag grass clippings or just use a side-discharge mower.