The Deep Dive Team explains the role of microbes in turf care
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About the Deep Dive
This audio discussion features members of the Deep Dive team – analysts who review the background material, challenge common misconceptions and translate technical information into clear, usable guidance.​​

​A Biological Approach to Croquet Lawn Management
For many years, thatch has been regarded as an unavoidable problem on fine turf croquet lawns, with mechanical scarification viewed as the only effective remedy. However, experience increasingly shows that this approach treats the symptom rather than the cause. Under an organically managed system, thatch can be reduced and controlled biologically, without the disruption and stress associated with aggressive mechanical practices.
Organic fertilisers behave very differently from synthetic chemical products. Rather than supplying nutrients as readily soluble salts, organic fertilisers rely on soil bacteria and fungi to break them down into forms the grass plant can use. This biological process is influenced by moisture, temperature and day length, which is why organic systems align so closely with natural grass growth cycles. As soil conditions improve in spring and summer, biological activity increases and nutrient availability rises steadily rather than in short bursts.  

One of the key advantages of this approach is its impact on thatch. Thatch is a complex layer of organic material including dead roots that accumulates in the root zone. It increases in thickness when the rate of production exceeds the rate of breakdown. Traditional chemical feeding programmes tend to stimulate top growth without enhancing soil biology, which can lead to increased thatch formation and a reliance on scarification to remove it. The thatch creates a spongy, slow surface which is not ideal for croquet because long shots become physically more difficult.

In contrast, the organic system I advocate focuses on increasing the rate of biological breakdown in the rootzone. One of the fertilisers I supply incorporates Biogran, which introduces a broad spectrum of beneficial bacteria alongside mycorrhizal fungi. These organisms work together to decompose organic matter within the thatch layer and rootzone, converting it into plant-available nutrition while improving soil structure and root function.
In practice, this biological activity reduces thatch levels by approximately 30% per year until a natural equilibrium is reached, where the rate of breakdown matches the rate of new thatch being produced. This is usually at a thickness of 5 to 8mm. At this point, thatch is no longer accumulating and routine scarification becomes unnecessary. This is why Biogran-based products are widely described as genuine “thatch-busting” fertilisers. Rather than tearing material out of the surface, they address the underlying imbalance that caused the problem in the first place.

The benefits extend beyond thatch reduction alone. Improved microbial activity enhances nutrient cycling, increases root depth, and improves resilience to stress. Lawns managed in this way tend to hold moisture more evenly, recover more quickly from wear, and show less susceptibility to disease pressure, particularly during periods of fluctuating weather.

It is important to recognise that this advice applies specifically to organically managed systems. Synthetic fertilisers do not rely on microbial conversion and therefore do not generate the same biological effects within the soil. Clubs following a chemical programme should not expect biological thatch reduction to occur at the same rate, and scarification may remain necessary under those regimes. Attempting to combine aggressive mechanical practices with an organic programme can also undermine the very soil biology the system is designed to encourage.

Mowing also plays a crucial role. The mowing heights and frequencies I recommend assume the use of a properly set-up cylinder mower of the type commonly used on croquet lawns. On flat croquet lawns, cut at 4 to 5mm during the season and 6 to 10mm in the winter, higher for undulating lawns.  Clean cutting, consistent height control and regular light mowing complement biological management by avoiding unnecessary stress and excessive leaf removal.

Ultimately, an organic approach to croquet lawn care is about working with natural processes rather than against them. By encouraging soil biology to perform the functions it evolved to do—nutrient release, organic matter breakdown and soil structuring—clubs can achieve firm, true-playing lawns while reducing reliance on disruptive practices. Thatch control, once considered a purely mechanical problem, can instead be managed as part of a balanced, sustainable turfcare system.