If I had to pick one thing that separates a thriving lawn from a struggling one, it's mowing height and frequency. And most people get it wrong.
The One Rule: The One-Third Rule
Never cut more than one-third of the grass blade at a time.
If your grass is 9cm tall, mow it down to 6cm. Not to 3cm, not to 2cm. This rule prevents stress, maintains root depth, and keeps your lawn dense and healthy.
Why This Matters
When you scalp your lawn (mow it too short), you:
- Stress the plant and weaken its root system
- Expose bare soil, inviting weeds
- Lose the protective leaf area that feeds the plant
- Make the grass more prone to disease
A lawn that's cut short recovers slowly and stays thin. A lawn cut to the right height recovers fast and gets thicker.
The Schedule
The one-third rule means you'll mow more frequently in spring and autumn when grass grows fast, and less frequently in summer and winter when it slows down.
Spring (September–November): Mow weekly. Growth is rapid.
Summer (December–February): Mow every 10–14 days. Heat slows growth.
Autumn (March–May): Mow weekly again. Second growth spurt.
Winter (June–August): Mow every 2–3 weeks. Dormancy period.
If your lawn is growing fast, you might mow twice a week. That's fine — it means your grass is healthy.
The Height Sweet Spot
For buffalo: Keep it between 4–7cm. Buffalo looks and feels better a bit longer.
For couch: 3–5cm is ideal. It tolerates closer cutting.
For kikuyu: 5–8cm. It's coarse and can handle length.
These aren't rules — they're guides. The key is never cutting more than a third.
The Mulch Mower Advantage
Mulch mowers (which don't bag clippings) return nutrients to the soil. Bagging sends those nutrients away and means you'll need more fertiliser to compensate.
If you mulch-mow and follow the one-third rule, your lawn often needs no extra feeding.
Real Talk on Drought
In drought, lawns go dormant and stop growing. Don't mow dormant grass — you'll damage it. Wait until growth resumes. That might mean one mow every 3–4 weeks in peak summer.
The Result
Mow frequently to the right height, and your lawn will:
- Recover faster from damage
- Outcompete weeds naturally
- Develop deeper roots
- Look denser and more uniform
- Need less water and fertiliser
It sounds counterintuitive — mow more to get a better lawn. But it works. The one-third rule is the foundation of every good lawn we've helped manage.
Start this week. Set your mower higher and mow more often. In three months, you'll see the difference.
