The Balance Between Growth, Health & Maintenance
Lawn thatch is one of those things that often flies under the radar—until it becomes a problem. That springy, fibrous layer of dead stems, roots, and shoots between the grass blades and soil surface isn’t inherently bad. In fact, a thin layer can help insulate roots and retain moisture. But when thatch builds up too thick, it can choke your turf, limit nutrient uptake, and reduce water infiltration.
The good news? With the right approach to mowing, feeding, and supporting your soil biology, managing thatch is easier than you might think.
Mowing Height: Small Changes, Big Impact
Cutting your lawn too short (known as scalping) can stress your turf and encourage shallow roots. On the other hand, mowing too high can lead to excessive leaf growth and more thatch accumulation.
Recommended cutting heights:
Fine fescue & ryegrass: 25–40mm
Tall fescue: 40–50mm
Kikuyu & couch: 20–35mm
Maintaining a consistent mowing height encourages deeper roots and supports microbial activity near the surface—exactly where thatch lives.
Tip: Keep your mower blades sharp to reduce tearing and stress on the grass.
Fertilising Smarter: Avoiding the Growth Surge
Not all fertilisers are created equal when it comes to thatch. Fast-release nitrogen can cause aggressive top growth that quickly adds to the thatch layer.
Instead, choose controlled-release granular fertilisers like:
LAWNZ Amplify
A slow-release nitrogen blend that supports steady, even growth and long-term turf colour.
LAWNZ Essential
A balanced NPK formula with added trace elements to condition the soil and promote year-round turf health.
By feeding your lawn gradually, you support strong roots without overloading the surface with excessive biomass.
Turf Species: Some Are Thatchier Than Others
Different turf types break down thatch at different rates. Understanding your lawn’s grass species helps tailor your approach:
- Fine fescue and ryegrass break down thatch more easily due to better airflow and microbial activity.
- Kikuyu and couch produce dense stolons and rhizomes that create thicker thatch layers if not well-managed.
- Tall fescue tends to build less thatch but can still develop issues under high-nitrogen conditions.
Microbial Support: Let Nature Do the Work
Healthy soil biology is your lawn’s built-in cleanup crew. Microbes help decompose organic matter in the thatch layer and improve overall soil structure.
LAWNZ Soil Boost
A premium microbial stimulant designed to:
- Enhance nutrient cycling and root health
- Accelerate thatch decomposition
- Support lawn recovery after coring or dethatching
Application Tip: Apply Soil Boost 3–4 times during the growing season (no more than once per month) to maintain a healthy, active microbial population.
When Thatch Takes Over: Time to Dethatch
If your lawn feels bouncy underfoot or starts to look patchy despite good watering, a thick thatch layer may be the culprit.
You may need to dethatch when:
- Thatch thickness exceeds 10–15mm
- The lawn is actively growing (spring or early autumn is best)
Follow up dethatching with LAWNZ Soil Boost and LAWNZ Essential to support microbial rebalancing and lawn recovery.
Lawn Coring: The Secret Weapon
Coring (aeration) isn’t just for compacted soil—it’s also an effective tool for managing thatch. Pulling plugs from the lawn exposes the thatch layer to oxygen and beneficial microbes, speeding up decomposition.
Benefits of coring include:
- Improved oxygen and water flow
- Faster microbial breakdown of organic matter
- Better uptake of fertilisers and soil amendments
Pair coring with Soil Boost to supercharge microbial activity, and follow up with Amplify or Essential to keep your lawn strong.
Final Thought: Thatch Is About Balance
A little thatch is a good thing—it insulates and protects. But too much becomes a barrier. By mowing thoughtfully, using slow-release fertilisers, and supporting soil biology with Soil Boost, you’re not just keeping thatch in check—you’re building a healthier, more resilient lawn from the roots up.
