Should You Mulch or Bag Grass Clippings?

A close up on grass.

Some homeowners wonder if they should mulch or bag grass clippings, or do both at different times for the best results. We've all seen yards that have been mowed that look like they have rows of hay spread about from the dead grass discharged by mowers.

A Mulching Blade

Lawns that look striped with dry, dead grass were mowed with machines that aren't designed for mulching. Standard side-discharge mowers don't grind the grass small enough to be considered mulched. Mowers must be equipped with a mulching blade to do this. This causes the cut grass to be re-cut several times before it's fine enough to fall through the blade to the lawn.

Benefits of Mulching

Mulching your lawn with this process lets the ground retain moisture and helps fertilize your lawn. Grass clippings are 80% water and will decompose quickly, releasing many nutrients. It also makes erosion less likely and keeps you from having to bag clippings and dispose of them.

Also, did you know that bagged grass clippings make up 20% of solid waste collected in the U.S. every year? A single acre of grass yields three tons of clippings using around 260 bags per year. Even if you choose not to mulch your grass clippings, you should consider using them in your compost heap instead. Grass clippings are full of beneficial nutrients such as nitrogen, phosphorus, potassium, and micronutrients. Don't contribute to our landfills by throwing away helpful (and free) fertilizer.


Too much mulching may cause thatch. Thatch is a layer of dead roots, crowns, and shoots of grass that form between the soil and the healthy green vegetation. Some thatch is normal for any lawn. Excessive thatch layers, however, can cause problems. Too much thatch can lead to disease and watering and rooting problems that can kill off portions of your lawn. Thatch is caused by a number of things including lawns that are overly fertilized with nitrogen. This causes the grass to grow very quickly and not be able to be broken down properly by microbes. Too much nitrogen could be a result of over mulching with grass clippings. During dry periods, excessively hot periods, and after fertilization are the best times to mulch. Bag grass clippings when it appears that the grass is building up or your lawn is becoming thatched. Store the bagged clippings for spring or add them to your compost heap.