Plastic weed barrier blocks weeds, but it also blocks water, air, and soil life.
Black plastic sheeting is one of the cheapest weed suppression options you can buy. Roll it out, pin it down, cover it with mulch, and forget about it. Except Australian UV shreds unprotected polyethylene within a single summer, and the water pooling underneath kills everything you actually wanted to keep alive.
Here is every trade-off between plastic sheeting and permeable weed mat, with product specs and installation numbers so you can order the right material first go.
Already know you need weed mat? Jump straight to choosing the right weed mesh for your project or browse the full weed mat range at All Stake Supply.
A plastic weed barrier is a sheet of polyethylene (usually black, 150 to 200 microns thick) laid over soil to stop weed growth. Plastic weed barrier works by blocking 100% of sunlight, which prevents photosynthesis and kills any vegetation underneath.
Unlike woven landscape fabric, plastic sheeting is completely impermeable. No light gets through, and no water or air gets through either. That is the catch.
The problem starts when plastic sheeting goes into a permanent garden bed, pathway, or planting zone. That is where the cheap fix turns into an expensive rip-out job.
The single biggest difference between plastic sheeting and woven polypropylene weed mat is permeability. Woven weed mat lets water and air pass through to the soil while still blocking 95 to 98% of light. Plastic blocks everything.
| Feature | Black Plastic Sheeting | Woven Polypropylene Weed Mat |
|---|---|---|
| Water permeability | None (0%) | High (passes through weave) |
| Air exchange | None | Yes |
| Light block | 100% | 95-98% |
| UV resistance | 1-2 seasons exposed | 5-15 years (UV-stabilised) |
| Soil health impact | Kills soil biology | Maintains healthy ecosystem |
| Tear resistance | Low (punctures easily) | High (woven structure) |
| Drainage | Water pools on surface | Drains through fabric |
| Professional use | Solarisation, temporary cover | Permanent landscaping, pathways |
A Black Woven Poly Weed Mat at 85 gsm suits residential garden beds and pathways. For commercial-scale projects, the 110 gsm woven poly weed mat lasts a decade or more under mulch.
Plastic weed barrier has legitimate uses, but they are all short-term. If you plan to remove the plastic within a season, it works well. Leave it in the ground permanently, and you are setting yourself up for drainage problems and dead soil.
Anyone who has stripped old plastic sheeting out of an established garden bed knows what is underneath: pale, compacted soil with no worm activity and no structure. Recovering that takes multiple growing seasons of compost and aeration, which is far more expensive than laying proper weed mat from the start.
Whether using plastic for a short-term job or woven weed mat permanently, correct installation determines how well the barrier performs. Most failures trace back to poor site prep or skipping the mulch cover.
Tip: Covering weed mat with 75-100 mm of mulch reduces UV exposure and often doubles the effective lifespan of the material. Never leave woven weed mat exposed to direct sun.
A lot of the advice you will find online about plastic weed barriers is written for US and UK conditions, where UV index peaks at 6-8 in summer. Australia's UV index regularly exceeds 11 and often hits 14+ in northern regions. That means every plastic product exposed to Australian sun degrades faster than overseas guides suggest.
Exposed polyethylene loses tensile strength rapidly under Australian UV. Black plastic sheeting left without mulch cover goes brittle within a single summer, cracking into fragments that mix into the soil as microplastics.
A 2024 PNAS Nexus study put the global figure at roughly 6.7 million tonnes of non-biodegradable plastic mulch entering soil systems every year. Once plastic breaks down in your garden, those fragments stay put.
All Stake Supply is family-owned and has been stocking weed control products from their St Marys warehouse since 1976. Fifty years of watching what lasts and what falls apart in Australian sun is why the team steers every permanent project toward woven weed mat.
If you are reaching for plastic because of the upfront price, consider the total cost of ownership. Low-cost plastic lasts one season and leaves microplastic fragments behind.
A proper woven weed mat lasts 5-15 years. Over five years, the woven mat costs less per year by a wide margin.
The standard choice for permanent weed suppression. Woven poly at 85-110 gsm handles pathways, garden beds, and civil works. Water drains through, air reaches the soil, and roots stay healthy.
A biodegradable alternative that suppresses weeds for 18-24 months, then breaks down and feeds the soil. Jute matting at 620 gsm suits revegetation projects and garden beds where you want weed suppression while new plantings establish. The 750 gsm option provides longer protection.
Coconut fibre matting handles salt spray and coastal conditions better than jute. Coir matting at 400 gsm is the standard for coastal revegetation and erosion control. Coir decomposes over 24-36 months, leaving no synthetic waste behind.
Woven polypropylene weed mat rated at 85 gsm or higher is the best long-term weed membrane for Australian conditions. It blocks 95-98% of light while allowing water and air through, and lasts 5-15 years under mulch or gravel cover.
Woven polypropylene weed mat for permanent applications. For temporary suppression around new plantings, jute matting at 620-750 gsm decomposes after 18-24 months. Both outperform plastic in longevity and soil health.
Pin the barrier with landscape staples every 200-300 mm along edges and seams. Overlap joins by at least 150 mm. Cover with 50-75 mm of mulch or aggregate to hold it in place and protect against UV.
Yes. Without weed mat, soil migrates upward through pebble layers and weed seeds settle between the stones. A woven weed mat stops both problems while letting rainwater drain through.
Exposed black plastic lasts one to two seasons in Australian sun before becoming brittle and tearing. Under thick mulch cover it may survive three to four years, but the lack of water and air exchange damages soil the entire time.
Yes. Plastic sheeting blocks all water and air exchange, killing earthworms, beneficial fungi, and soil microorganisms over time. Soil under old plastic sheeting becomes compacted and structurally poor.
Only for short-term applications like soil solarisation or seasonal vegetable beds where the plastic will be removed within a few months. For anything permanent, basic black plastic degrades into microplastic fragments and creates a worse problem than the weeds.
For residential garden beds and pathways, 85 gsm woven polypropylene is sufficient. For commercial landscaping and high-traffic areas, 110 gsm or higher provides greater tear resistance and a longer lifespan under Australian UV conditions.
Use plastic for solarisation, seasonal veg beds, and temporary construction cover. For everything else, woven polypropylene weed mat handles Australian UV, lets water through, and lasts years longer.
Browse the full product range at All Stake Supply or contact the team for trade pricing and bulk orders. With 1,000+ products in stock at the St Marys NSW warehouse and guaranteed complete delivery, your order ships whole, not in pieces that hold up your site.
