fbclpastor
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Will Underlayment Over Weeds Kill the Weeds?

I've got a completely out of control (huge) mulch bed with bushes. Sod is practically growing in it. I'd rather not have to shovel out all the weeds/grass. Is there any way I could just put the underlayment down over the weeds, and then new bark? Won't it kill the weeds that are there? Why do I already know the answer is going to be no?

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pinksand
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Re: Will Underlayment Over Weeds Kill the Weeds?

I'm not sure about underlayment... I just think of sub flooring like plywood when I hear that term so I'm not sure exactly what material you mean. I've layered newspaper in weedy beds in the past and that has worked pretty well. I'd recommend layering about 5 sheets, watering it well, then cover with mulch. It suffocates the weeds and decomposes so that you don't have to worry about nasty weed blocker plastic or fabric.
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fbclpastor
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Re: Will Underlayment Over Weeds Kill the Weeds?

Great tip, thanks.

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ElizabethB
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Re: Will Underlayment Over Weeds Kill the Weeds?

Fbclpastor.

You can try the newspaper but use a lot more than 5 sheets. You can also try cardboard from appliance boxes.

I really hate fabric in a bed. You can not cultivate. You will eventually have to remove it which is an unbelievable pain.

Your best bet is to remove the weeds. Add soil if needed. If you are not adverse to chemicals work in a pre-emergent - Amaze or Preen. Read and follow the label directions. Good for about 6 months of weed control.

Once the beds are cleaned add a thick layer of mulch. If you use wood mulch use 4". Wood mulch is good for water retention but really does not do much for weed control. A thick layer of pine straw is great for both water retention and weed control. Get bales of pine straw and put down a VERY thick layer - 8" to 12". It will be a little unsightly in the beginning but will quickly pack. Once it has packed it is very attractive and few weed seeds will be able to germinate. Pine straw decomposes slower than wood mulch so you do not have to replenish as often. NO the pine straw will not have an adverse affect on your soil. The decomposing pine straw does not significantly lower the pH of the soil.

Good luck
Elizabeth - or Your Majesty

Living and growing in Lafayette, La.

When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant. ~Author Unknown

imafan26
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Re: Will Underlayment Over Weeds Kill the Weeds?

Thick card board might work. An old carpet will block out light and roofing paper is thicker and more puncture proof.
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PaulF
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Re: Will Underlayment Over Weeds Kill the Weeds?

I also like newspaper as the first layer. Make that 4-5 layers. Depending on where you live the next layer I would rather use is wheat straw or pine straw if it is plentiful where you are. No pine straw in the midwest but lots of other straw. And I agree to make it thick. Newspaper and straw allows rain or watering to soak through to the soil and will not allow the weeds to poke through. Then at the end of the season it can all be tilled into the soil as organic material. Bark or wood chips will decompose but it will take a lot longer. Carpet, roofing paper and plastics will block weeds but moisture won't go through as easily.
Paul F

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