Does Mulch Stop Weeds? Yes, Here's What Works
You've just weeded the bed and you don't want to do it again in six weeks. Mulch is the fix, and depth matters more than which mulch you buy. We've grown and mulched tea tree at Teven, near Ballina, for over 20 years, so here's what works.
Yes. Mulch stops weeds by blocking the light weed seeds need to sprout, so depth matters more than mulch type. 75mm is the sweet spot. Under 50mm, weeds find the light. Over 100mm you gain nothing and your plants start to suffer.
How does mulch stop weeds?
Most weed seeds won't sprout without light, and a solid layer of mulch takes that light away. That's the whole trick, so depth beats mulch type every time. Tea tree helps by knitting into a tight mat with no gaps for daylight. It's one species off one farm too, so there's no weed seed hiding in the load.
How deep does mulch need to be to stop weeds?
Lay it 75mm deep and keep it even, because weeds find any thin patch. One cubic metre covers 13.3 square metres at that depth. Go a bit thicker on slopes and ground with a bad weed history.
How do you lay mulch so it actually stops weeds?
Mulch stops new weeds sprouting but can't kill what's already up, so do this first.
- Weed the bed properly, roots and all, and dig out nutgrass and bulbs.
- Cut a clean edge against the lawn so runners can't sneak in.
- Soak the soil, then spread 75mm in one even layer.
- Water it in so the fibres knit into a mat, and keep it clear of trunks and stems.
How often do you need to top up mulch to keep weeds down?
A 75mm layer lasts 12 to 18 months here, so top it back up when it thins. Late winter to early spring is the best window, just before the spring weeds move. Work out your area with our calculator, then ring 0402 294 776 for a price to your address. We deliver across the Northern Rivers seven days.
Mulch settles, so order a little more than the calculator says.
Related questions
Does tea tree mulch kill weeds?
No mulch kills weeds. It stops seeds sprouting by blocking their light, but can't touch a weed that's already up. Weed the bed first, then lay 75mm and the next lot never starts.
How much does one cubic metre of mulch cover?
One cubic metre covers 13.3 square metres at 75mm deep, or about 10 barrow loads. Measure length by width, then add a little extra because mulch settles.
What are the downsides of using mulch for weed control?
Not many if you lay it right. Keep it at 75mm so water gets through, don't dig it in, and cut a clean lawn edge so runners can't creep in.
Is it worth putting weed mat under mulch?
We'd skip it. A 75mm layer already blocks the light and feeds the soil as it breaks down, which weed mat never does. Windblown seed sprouts on top of the mat anyway.
How much does tea tree mulch cost for a weed control job?
It depends how much you need and how far we drive, so call for a price on 0402 294 776, any day between 8:30am and 5pm, and we'll work it out.
