The case for leaving them
Short clippings from a regular cut are mostly water. They fall down into the base of the sward, break down within a few days, and give the nitrogen they were holding straight back to the soil.
Do it every mow through a growing season and it is a genuine reduction in how much fertiliser the lawn needs, at no cost and no extra work. It also puts a small amount of organic matter back into the soil, which sandy Central Coast blocks are usually short of.
When to run the catcher instead
- The grass got away from you. Long clippings sit on top in mats rather than dropping through, and a mat thick enough to block light will kill the lawn under it.
- It is wet. Wet clippings stick together and clump, whatever the length.
- Weeds have seed heads on them. Mulching in that case is broadcasting weed seed evenly across your own lawn.
- There is disease showing. If part of the lawn has a fungal problem, catching stops you carrying it to the clean parts.
- You want the sharp finish. A caught lawn simply looks tidier straight after the cut, which matters for an inspection or a party.
Do clippings cause thatch?
No, and this is the most persistent myth in lawn care. Thatch is the layer of dead stems, runners and roots that builds up between the leaf and the soil. Clippings are almost entirely leaf and water, and they break down far too quickly to contribute.
Thatch in a Central Coast lawn is much more likely to be coming from vigorous kikuyu or couch runners, over-feeding, or mowing too low too often.
What to do with a full catcher
Grass clippings compost well, but only mixed with something dry and carbon-rich — leaves, shredded paper, mulch. On their own in a heap they go slimy and smell. Failing that, they go in the green bin.
How a Shane visit handles it
Every mow finishes with edging and a full blow-down, and green waste is cleaned up before we leave. Catching or mulching gets decided on the day, based on how the lawn has come up.