Most mowers today have very efficient mulch-mowing modes, I explain a bit about blade types and mulching in the video below.
Mulch-mowing cuts & re-cuts the grass clippings to a very fine state before blowing them back into the lawn. These clippings break down very quickly adding nutrients and organic matter so it’s like giving your lawn and soil a light organic feeding every time you mow.
Mulch-mowing is also faster – you’re not stopping & starting to empty the catcher – and gives a more even cut – mowing with a catcher the mower sinks into the lawn as the catcher fills leading to changes in cutting height.
If you want the best possible lawn they you should be mulch-mowing every time you mow with a few exceptions;
- if the grass is really long, mow it in two passes. The first with the catcher on, the second on mulch-mow mode.
- don't mulch-mow if the grass is really wet as the clippings will clump up too much.
- in anything but the warmest areas don't mulch-mow across the cooler months. The reason for this is that the breakdown of the clippings relies on biological activity in your soil and grass thatch. This activity slows down in winter and clippings can sit around the grass roots for too long causing fungal problems.
So my professional opinion is that if you want the best looking & healthiest lawn and healthiest soil beneath your lawn then whenever possible you should be putting the clippings back onto the lawn through mulch mowing. - Adam_W
I always go with the catcher. My two puppies always trek it through the house or eat it otherwise. As a kid I do remember my dad spreading it onto some of the garden beds. - sburatto
If you have a mulching mower, it can create very fine pieces of cut grass that do provide nutrients for the lawn and soil. It's obviously fine right now but my understanding is that you shouldn’t put the clippings on in winter as the mulch won’t break down as fast as it does in the warmer conditions, which can cause problems.
Remember not to cut the grass too short, either! If you cut the grass too short it doesn’t have enough leaves for photosynthesis and might be weakened. - Isobel
I rarely use the catcher (just occasionally in winter) and haven't had many problems with clippings spreading around. I use a mulching mower which makes pieces fine enough that they fall into the thatch and don't really spread too far. I've got a buffalo lawn which I leave a lot of height on which also helps I guess. - Eric
I've heard that leaving some clippings on the lawn is good to mulch or fertilise the lawn, but I reckon at the wrong time of year you wouldn't want to leave it all on. You need to make sure the grass gets plenty of sun. And remember not to mow too low. - Baz
We had a Flymo hover mower, which mulched the clippings very finely and left the lawn looking neat. No problem in the drier seasons, the mulch sheltered the turf, quickly broke down, and returned nutrients. In the wetter seasons the damp mulch clogged the lawn, eventually suffocated it and black mould set in.
From my experience, you're better off collecting your clippings in the wetter months and dealing with them in composting bays, bins, or tumblers. - Andy_Mann
Depends on the length of grass and weed content. If the grass is high or weedy then disposing the clippings is a sound strategy. For a well cared for lawn then using a mulching plug on the lawn mower is the way to go. This adds some nutrients to the lawn and also prevents burning from the sun. - popawisky
The 'it’s good for the lawn dear' line doesn't cut it when the kids come inside covered in clippings from falling over outside. Green waste bin if weedy, compost if grassy. Plus the boys love playing with rakes, brooms & their little gardening gloves so it becomes a fun game to put the clippings away. I would feel terrible taking away from their positive attitude. - tetris36
The results from our Bunnings Workshop community poll were 36% who do leave their clippings to add nutrients back into the soil, and 64% who prefer to keep their catcher on and dispose of the clippings elsewhere. - Jason