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How To Stop Weeds From Growing In Mulch

The problem of weeds in your garden isn’t something off the wall. Gardeners have been experiencing weed infestation since the old days, and your case is no exception.

One of the conventional ways of eliminating weeds in your garden is by mulching. In fact, mulching works quite well in keeping away these unwelcome guests from your garden.

If mulching works that well, what should you do when you notice weeds growing in mulch? Of course, you would be left scratching your head.

Your obvious next step would be to figure out how you can rid your garden or backyard of pesky weeds. Let’s have some insights.


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1. Put A Weed Barrier Underneath Your Mulch 


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One easy way to stop weeds growing through mulch would be to use weed barriers. The weed barrier is locally available in retail stores, or you could order them online.

The plastic material complements the efforts of your mulch material as a physical barrier against weeds. Given the many types of weed barriers you will find in stores, we advise going for the black ones.

Clear weed barriers may help you see the weeds, but they aren’t compelling enough since they still allow light to go through them. That said, having clear weed barriers is more effective than having no weed barrier at all.

The question lingering in your mind right now is how your plants are expected to grow through the weed barrier. We advise strategic cutting of X shapes through the barriers.

Your sole intention here should be to allow your plants to poke through the holes in the barriers. Cutting X shapes works well in a garden with plants growing from seed.

Just cut the X shapes in areas the plants are supposed to grow, and everything will work out fine. You can now spread a layer of mulch on top of the weed barrier.

Use Old Newspapers As Weed Barriers 

Some gardeners are environmentally conscious and wouldn’t want to use a non-biodegradable material. In that case, we recommend making use of old newspapers as a weed barrier underneath the mulch.

This helps you protect your garden against weeds while holding on to your environmental stance. Old newspapers are an ideal alternative to the typical commercial weed barriers.

The advantage of using newspapers is that they are biodegradable; however, you will need to replenish them regularly compared to a commercially available weed barrier.

Newspapers prevent weeds from sprouting through the mulch. Use several layers. Besides, they are biodegradable and decompose, adding nutrients to the soil. 

2. Thicken The Mulch Layer 


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Mulch in your garden helps in controlling weeds by denying them light access. However, sometimes the mulch may not be thick enough to keep sunlight away.

Weeds getting sunlight means they will continue to grow. How about laying more mulch?

Lay mulch that measures up to 7.6 cm thick to block sunlight and prevents the weeds from growing. Replenish the mulch once in a while to cover for decomposition and the mulch material getting blown away. 

3. Hand Pull Weeds


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Let’s face it. Weeds are very resilient, and sometimes they will grow through your mulch.

Here is where you want to think outside the box and see whether you can fix the problem differently.

Hand-pull the weeds by their roots out of your garden. This could be quite tedious, but it’s worth the effort since it will eventually pay off.

Make use of a trowel to help you pull the weeds by their roots out of the soil.

Preferably, you should do this before laying the mulch to ensure you thoroughly uproot the weeds out of your garden. 

4. Stop the Weeds With A Herbicide 


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If you feel hand pulling the weeds is quite strenuous for you, we advise using pre-emergent herbicides on your garden before laying the mulch.

You want to apply them in early spring before the weeds sprout. The pre-emergent herbicides won’t be as effective should you apply them after the emergence of weeds.

Do this stepwise: 

  • Rake off any mulch material aside. 
  • Uproot or get rid of any emerging or pre-existing weeds. 
  • Apply the pre-emergent herbicide following the manufacturer’s manual. Be keen on the label as some plants are intolerant to certain types of pre-emergent herbicides. 
  • Carefully replace the mulch without disturbing the treated soil. 

After the above steps, you can add another layer of pre-emergent liquid herbicide on top of the mulch as an additional layer of protection.

Using liquid herbicide is ideal since it will stick to the mulch rather than falling through to the soil. 

You could also use a broad-spectrum herbicide like glyphosate to de-weed a heavily infested mulch area. However, using glyphosate requires extreme caution since the herbicide eliminates any broad-leafed plants it comes in contact with.

The trick is to apply glyphosate to weeds by using a paintbrush while avoiding nearby plants as much as possible. You can also use cardboard to protect the other plants during application.

Ensure the treated weeds are completely dry before removing the cardboard. For a more eco-friendly approach, consider using a mix of salt, vinegar, and dish soap to eliminate the weeds as they grow. 

5. Construct Borders Around Your Mulched Areas


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A heavy infestation of weeds in your mulched areas could also be caused by encroaching weeds from a parallel lawn or flowerbed. Weeds and grass growing in your neighbor’s yard could also begin spreading their roots into your garden.

A border helps to prevent the roots and runners from taking over your mulched areas. Dig a trench around your garden and create a border using pavers, rocks, or bricks.

These materials help prevent weeds from encroaching and growing through mulch. Besides, they add aesthetic value to your garden. 

6. Water Only The Desired Plants And Not The Weeds 

Another way to prevent weeds from growing in mulch would be to deny them water.

Like any other plant, weeds love water, and denying them this precious resource eventually eliminates them. The drip irrigation system can best achieve this purpose since it only sprays water around the roots of your desired plants.

The weeds growing in mulch will suffer water stress and ultimately fail to sprout. 

7. Plant Ground Cover Crops


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Ground cover plants that grow and spread across the ground can easily take care of the weed menace in your garden.

Weeds usually sneak into the space between your garden plants. Growing ground cover crops means that the weeds will have little to no room to grow.

Some suggestions for ground covers include Catnip, Mint, and Rosemary. These ground cover plants also add to the overall aesthetics of your garden.

8. Hire A Professional  

Why not hire a professional if your budget allows. A professional could help you provide tips on what mulch to use in different areas of your garden.

For example, you may want to use shredded bark for landscaping. It has a coarse texture and takes time to decompose.

It also doesn’t blow away easily, making it a good fit for blocking sunlight.

Your weed eradication program could efficiently work this way.

Some other materials to consider are Cocoa hulls, pebbles, and wood chips. We advise against using certain types of mulch, such as grass clippings, leaves, and pine needles.

These mulch materials decompose quickly, giving your weed more chance to sprout. What’s more, grass clippings carry seeds that add to the pool of weeds in your garden. 

Wrap Up

Mulch is a great physical barrier to keep weeds away from your garden. However, it has its fair share of challenges and may allow weeds to grow through.

There are several ways to prevent weeds from growing through the mulch, such as using a weed barrier, uprooting the weeds, using herbicides, and a few others. Choose whatever suits your budget.

Be aware that keeping weeds off your garden permanently isn’t possible, but the tips mentioned should help you keep them away for quite some time. 


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