Cork and Coconut Husk Infill vs Rubber Crumb in Australia

Why anyone went looking for a rubber crumb replacement

Rubber crumb has been the default dressing on synthetic sports pitches for decades. It is cheap, it cushions a falling body, and it gives scrap tyres a second life. It is also the single biggest escape route for microplastic from a synthetic surface. The European Chemicals Agency puts losses of granular infill from pitches at up to 16,000 tonnes a year, the largest single source of intentionally added microplastic pollution in the EU, and the European Commission adopted a restriction in September 2023 banning the sale of granular polymer infill from 17 October 2031.

Australia has no equivalent rule. The NSW Chief Scientist and Engineer's 2023 review of synthetic turf in public spaces landed on a learn and adapt position rather than a ban, and called for further research. Imported SBR crumb is made from scrap tyres, and it inherits whatever chemistry those tyres had. Our guide on whether artificial grass is bad for the environment works through that research properly. Either way the outcome is the same: a real market for infill made from cork bark and coconut husk.

What the organic infills are made of

Cork infill is granulated bark from the cork oak, stripped roughly every nine years without felling the tree, which is the basis of cork's sustainability story. Granules sold for turf are typically one to two millimetres across. Cork's closed-cell structure traps air, so it weighs very little, holds moisture without turning to sludge, and conducts heat poorly.

Coconut husk infill is milled and screened coir, the fibre left over from coconut processing. It holds a lot of water for its weight, and evaporation from that stored water does most of the cooling work.

Most commercial products blend the two, and nearly all sit on a stabilising sand layer rather than replacing sand. The cork fraction stops the coconut compacting into a dense mat.

The named products

Three suppliers dominate the conversation.

GreenPlay Organics, part of Sprinturf, makes Corkonut, a coconut fibre and cork blend it describes as America's original organic infill, and says it has gone into over 60 full-size fields. Its newer EVO product is 100 per cent coconut husk and fibre. GreenPlay claims the lowest turf and infill system temperatures of any sand, rubber or plastic infill, which is the company talking about its own product.

FieldTurf sells PureFill, granulated cork that it specifies as a top layer over a sand ballast, with a shockpad beneath. The company states that all of its infill materials meet or exceed EN 71-3, the European heavy-metal migration limits for children's toys. FieldTurf has an Australian arm that lists PureFill, which makes it the most reachable of the three from here.

Amorim, the Portuguese cork group, supplies cork infill under its Nature line and claims surface temperature reductions of up to 30 per cent against other infill solutions. It backs the environmental side with a cradle-to-gate life cycle assessment by ITECons to EN ISO 14040 and 14044, reporting a negative carbon figure for the cork itself because of biogenic carbon stored in cork oak forests. The supplier commissioned and published that assessment, so read the framing accordingly, though the carbon argument for cork is uncontroversial.

Does it genuinely run cooler

This is the claim worth taking seriously, because there is Australian measurement behind it. SportEng, an Australian sports surface consultancy, reports readings taken at 30°C ambient of 25°C on a natural grass field, 45°C on a cork field and 62°C on SBR rubber fields. A 17 degree gap is large, and it lines up with the physics: dark rubber granules absorb solar radiation and re-radiate it, cork insulates, and damp coconut husk sheds heat by evaporation.

The catch sits in the word damp. Evaporative cooling stops when the water runs out, so fields on organic infill often need irrigation through summer to keep it working, an awkward position for a surface many people buy specifically to stop watering. Cork suppliers push back on that reading, and FieldTurf's own material claims a significantly cooler surface without the need for irrigation, so treat the point as contested.

For scale, the independent measurements cited in our guide on whether artificial grass can burn bare feet put synthetic grass in full Australian sun in the 70°C to 100°C range, while APT, the manufacturer behind our range, states a normal design range of roughly 65°C to 75°C in its own brochure. Under either figure, no infill choice turns a January afternoon into a barefoot surface.

How the three infills compare

Factor	Silica sand	Rubber crumb (SBR)	Cork and coconut husk
Surface heat	Moderate, lighter colour	Hottest, dark and absorbent	Coolest while moist
Microplastic from infill	None, it is a mineral	The main escape route	None
Weight and stability	Heavy, stays put	Light, migrates	Very light, floats in heavy rain
Behaviour over time	Compacts slowly	Degrades slowly	Breaks down, needs topping up
Cost	Cheapest, widely stocked	Cheap, widely stocked	Dearest, limited AU supply
Typical use	Home lawns	Sports fields	Fields chasing lower heat

Where organic infill struggles

Flotation comes first. Cork and coconut husk weigh little enough that heavy rain lifts them, and the material migrates to the edges or washes off where water pools. GreenPlay disputes this for its own blend and says displacement and fly-out are virtually eliminated. Density works against the material either way: granules light enough to be lifted by moving water drift to the edges when a downpour outpaces the base's drainage, which is what an east coast summer storm does.

Breakdown comes second, and it is the whole point of the product. Organic infill biodegrades, and under foot traffic it breaks into finer particles, compacts and loses depth, which gets worse once the material dries out and turns brittle. That means regular top dressing to hold the layer at spec. Sand compacts as well, with the difference that sand stays put.

Availability is the practical blocker here. PureFill is listed by FieldTurf's Australian operation, which quotes into projects rather than selling bags off a shelf, and GreenPlay's blends have no Australian distribution I could find. Small retail bags of cork granulate exist through specialty cork retailers offshore, where freight on a bulky low-density product works against you.

What this means for a home lawn

The problem organic infill was built to solve is mostly a sports field problem.

Rubber crumb exists for shock absorption and ball response on pitches where players fall at speed. Nearly every Australian residential lawn is ballasted with kiln-dried silica sand instead, so there is no rubber in the yard to swap out in the first place. Our silica sand versus rubber crumb comparison walks through that decision, and a 30mm to 40mm landscape pile already feels softer underfoot than a sports surface.

The heat argument survives the move to a backyard, though at home it gets attacked in the yarn and in the shade plan. Coolplay Green carries APT's COOLplus treatment, which the manufacturer claims reduces the temperature of artificial grass by up to 20 per cent, and Classic 40 GT uses their HeatBlock technology. Both are manufacturer claims rather than independent findings, and neither makes turf cool. Shade over the part of the yard that gets used, plus a hose down before the kids go out, does more than any infill decision. Each product page carries current pricing and a calculator that turns your measurements into a length, since turf ships in fixed cut lengths (commonly 5m, 10m, 15m or a full 20m roll) at a 3.71m roll width, and a wider yard means joining two runs. We deliver everywhere except Western Australia and South Australia.

Lifespan moves the environmental number far more than infill does, and a well-brushed lawn on a properly built base stays down years longer than a neglected one before it becomes the problem described in our guide to turf recycling in Australia.

Frequently asked questions

Can I use cork infill on a residential artificial lawn in Australia?

Technically yes, though sourcing it in backyard quantities is the difficulty. FieldTurf Australia lists PureFill, but it is quoted into projects rather than sold by the bag, and GreenPlay's blends have no Australian distributor I could find. Small bags exist through specialty cork retailers offshore, where shipping a light bulky product across the world eats the budget.

Is cork or coconut infill better for a lawn with a dog?

Neither is an obvious improvement over sand for pets. Organic infill holds moisture by design, which is the opposite of what you want under a dog that uses the same spot daily, and a damp organic layer suits odour-causing bacteria better than a free-draining mineral one. Silica sand rinses clean and pairs with the antimicrobial yarn treatments on our pet products. Our turf for pets page covers the choices that matter more here.

Does organic infill really biodegrade, or is that marketing?

Cork and coconut husk are plant materials and they genuinely break down, which is also why they need topping up. The limit on the claim is that the carpet above them is still polyethylene or polypropylene yarn on a latex or polyurethane backing, most of the plastic in a synthetic lawn by weight. Swapping the infill improves the picture at the margins while leaving the main material untouched.

How much does organic infill cost compared with silica sand?

Expect a clear premium, though a reliable Australian retail figure is hard to pin down because these products get quoted into sports projects rather than sold off a shelf. Kiln-dried silica sand is stocked by the bag at most landscape suppliers at ordinary sand prices. For general market context, Australian rates run roughly $15 to $30 per square metre for budget 15mm to 25mm pile supply only, $30 to $45 for mid-range and $40 to $60 for premium, all including GST, with professional installation typically adding $30 to $70 per square metre.