When deciding how to mow your lawn for best results, it’s common to question the merits of mulching vs. side discharge. In most applications, side discharge mowers are more versatile and perform better than mulching mowers. Mulching mowers are best used in small yards where the main goal is keeping grass clippings out of gardens and paved areas.
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Grass Clippings for a Healthier Lawn
The best way to mow for good grass health is to allow cut grass to be spread on the lawn. Grass clippings are a great natural fertilizer that returns nutrients to your lawn as they decompose.
Both side discharge and mulching mowers can return grass clippings from your yard. As long as you can mow with a side discharge mower in such a way that cut grass is discharged onto the lawn, it will provide the same benefits as a mulching mower.
If you are mowing a space where a side discharge mower would spray grass clippings into your garden or onto streets or sidewalks, then you are literally throwing nutrients out of your yard. In these applications, a mulching mower is best.
Should You Bag Grass Clippings?
If you bag your cut grass, you’re robbing nutrients from your soil and throwing them in the trash. Instead of decomposing in your yard, all that precious fertilizer is shipped off to a landfill. It is untrue that grass clippings promote thatch buildup—thatch is made up of old grass stems and blades that die with age. Thatch does not contain cut grass clippings.
What is the Difference Between Mulching and Side Discharge?
Side discharge mowers spray cut grass clippings out of a discharge chute, sometimes for a distance of several feet. Meanwhile, mulching mowers do not have a discharge chute. This means that grass cut by a mulching mower stays in the blade housing longer, often being cut into smaller pieces that are then dropped on the ground beneath the mower as you go. Mulching mowers give your greater control of where your grass clippings are deposited as fertilizer.
Side discharge mowers are the classic mowing choice, favored by many homeowners and lawn care companies. They provide a great cut but are generally messier than mulching mowers. It’s worth examining the pros and cons before making your choice.
Side Discharge Mower Advantages
- Faster blade speed allows for a cleaner cut when mowing.
- Allow non-stop operation and faster mowing.
- Good results cutting tall or wet grass.
- When cast in the optimal direction, discharged grass clippings are returned to the yard as a natural fertilizer.
- The best option for large yards where speed and efficiency is more important than cleanliness.
Side Discharge Mower Disadvantages
- Discharged grass and weed seeds can be cast into flowerbeds and gardens, where they can become invasive.
- Grass clippings can be thrown onto driveways, sidewalks, streets, etc. where they end up as trash, not natural fertilizer.
- Can spray a mess of grass clippings on houses, cars, and other structures in your yard.
- Discharge chute may throw rocks, sticks, and other debris.
Mulching mowers do not have a discharge chute. Instead, they feature an enclosed blade housing and are equipped with special mulching blades that finely cut mowed grass and return it to the ground as you mow, dropping fertilizing grass clippings right where they need to be. Although this all sounds positive, the lack of a discharge chute reduces the mower’s vacuum effect, which results in a lower quality cut and slower mowing.
Mulching Mower Advantages
- Do not spray grass clippings, so there’s no cleanup.
- Return cut grass to the yard as instant fertilizer.
- Keep valuable grass clippings out of gardens and off paved surfaces.
- Do not fling hazardous items out of the discharge chute.
- Best for small yards, or areas with extensive gardens.
Mulching Mower Disadvantages
- Slower blade speed means a lower quality mowing job.
- Require slower operation than side discharge mowers.
- Not well suited for mowing tall or wet grass.
- Not ideal for large yards.
Can You Use Mulching Blades with Side Discharge?
Many new mower models feature blades that are designed for use in both mulching and side discharge applications. While specialized blades for one specific method are available, multipurpose blades are becoming more common. If your mower is equipped with a multipurpose blade, it can be used for both mulching and side discharge.
Can You Mulch with a Side Discharge Mower?
If you’re sick of cleaning up grass clippings or spreading grass and weed seeds in your garden, you can easily convert your side discharge mower into a mulching mower. Simply purchase and install a mulching blade for your mower, as well as a restrictor plate that blocks the side discharge chute.
Mulching conversion kits are available for most side discharge mower makes and models and are easy to install. With just a few minutes of work, you can say goodbye to the mess of side discharge and start mulching.
OCDCs for Side Discharge Mowers
What’s even better than debating mulching vs. side discharge? Having both options at once. OCDCs, or Operator Controlled Side Discharge Chutes, are a modification available on many mowers. They allow you to open or close the side discharge chute at any time while mowing.
OCDCs are often operated by a cable control that you can operate at any time. That way, you can close your side discharge chute as you mow around the border of your garden, or near driveways or sidewalks. Then, you can open the discharge chute in other areas. This allows you to prevent spraying grass clippings at some times and reap the benefits of the speed and quality of side discharge at others.
Can You Convert a Mulching Mower to Side Discharge?
There’s no easy way to turn a mulching mower into a side discharge mower. Because mulching mowers have blade housing without an opening or a discharge chute, you would have to use metal-cutting tools to cut away a portion of the blade housing, then attach a discharge chute.
This sort of modification is not advised, as it may void warranties and render your mower unsafe to use. Typically, it’s much easier to turn a side discharge mower into a mulching mower (via a restrictor plate or OCDC) than it is to make a mulching mower into a side discharge machine.
Mulching vs Side Discharge Mower
Side discharge mowers provide the highest quality cut, work faster than mulching mowers, and can be easily modified for use mulching if the situation calls for it. This makes a side discharge mower a more versatile tool in your shed. If you’re mowing large, open areas, where you can direct cut grass back onto your lawn as fertilizer, side discharge is the best choice for lawn health.
Mulching mowers are more specialized and typically work more slowly and yield less pristine cuts than side discharge. Also, it’s not possible to easily convert a mulching mower to side discharge if the situation calls for it. However, mulching mowers do not spray grass clippings. Instead, they drop cut grass back onto the lawn. This makes them a great choice as lawn fertilizers. If you are mowing a small lawn or a yard where side discharge would spray grass clippings into flower beds and onto paved surfaces, then a mulching mower is the best choice.