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gcotterl

Weed barriers. Bad idea?

gcotterl
9 years ago

I've half-decided to thoroughly weeding a garden then install a weed barrier fabric topped with mulch in my garden to "almost" eliminate the never-ending weeds.

But today, I read an article saying that, installing a weed barrier fabric may not such a great idea. The article says:

"Weed seeds will blow into your beautiful mulch bed no matter what you do. Birds will also spread some weeds around for you".

"You may say, 'So what? I have fabric to keep them from growing'.

"No, you don't. All of that hard work (and expense) did for you is to guarantee even harder work in the not-so-distant future".

?So enjoy the first few weeks while you can. Those weeds will root right through that fabric".

"Why? Because fibrous roots will grow through a pin hole, and guess what you have then?... A complete mess, getting worse by the day. Have you ever tried to pull weeds that are rooted through a fabric as well as the earth beneath?"

"Take it from me, it is an utter nightmare! So not only will you have as many weeds as you had before, now removing them is harder than ever!"

"Solution... Deal with it or remove the mulch and tear up the weed barrier fabric!"

"Better solution.... DO NOT EVER USE WEED BARRIERS OF ANY KIND!...EVER!"

"Real Solution: Use pre-emergents at the appropriate time according to label. Then soften the ground & catch any weeds early!. If you follow these steps, your weeding will decrease every season, especially as your desirable ground covers take over, AND, your mulching bill will slowly disappear because your plants will now fill the voids to where there is no more room for mulch".

Since I hate the continual re-weeding chore, is a weed barrier fabric really a good idea or is there a better solution?

Comments (13)

  • zzackey
    9 years ago
    last modified: 9 years ago

    We never used weed barrier or pre-emergents. We just use grass we picked up from mowing the lawn as mulch. It works great. We get a few weeds, but they are very easy to hand pull.

  • NHBabs z4b-5a NH
    9 years ago
    last modified: 9 years ago

    I use cardboard or several layers of newspaper topped with 3'-6" of mulch. It blocks light and the few weeds that sprout in future years in the mulch are easy to pull. I haven't had issues with current weeds sprouting through the mulch as long as I have heavy mulch and I cut them down to ground level before mulching. I have a bed that's somewhere in the range of 15' by 60' and I doubt I spend two hours weeding it all season. I do have a solid edging around it to keep the grass, etc from growing into the bed.

    One thing not mentioned in the article you sited above is that current research finds that the weed fabric restricts movement of air, nutrients, and water into the soil below it, so it is actively harmful to the health of your plants.

  • gcotterl
    Original Author
    9 years ago
    last modified: 9 years ago

    As my previous post ("Kill weeds" dated on Sat, Oct 25) said, I've had poor success with the pre-emergent Preen.

    Cut grass is not available to me because I live in a condo development so the grass is mowed by a landscaping firm and taken away.

    The "mulch" I was considering is redwood bark (or other similar material) spread several inches thick on top of the weed barrier.

  • rhizo_1 (North AL) zone 7
    9 years ago
    last modified: 9 years ago

    I hope that you pay attention to the advice you've been given, both in that artlcle and within this forum. I'd worry about the health of your plants, too, with their roots covered both by the weed barrior AND 'several inches' of mulch.

    That's not good for roots nor for the soil system for a variety of reasons.

  • gcotterl
    Original Author
    9 years ago
    last modified: 9 years ago

    The weed barrier that I'm considering is a non-woven, hydrophilic treated fabric that allows air, water and fertilizer to pass into the soil for the shrubs and that minimizes light penetration to suppress weed growth.

    Example: DeWitt Pro-5 Weed Barrier

  • drmbear Cherry
    9 years ago
    last modified: 9 years ago

    Don't use any kind of fabric weed barrier. Think about it - your goal is to improve the soil so plants grow better. If you put down weed fabric, then mulch above it, all the stuff that can actually help the soil is being isolated from it. In some of the houses I've moved into, I've found that weed fabric under decayed organics full of weeds, with soil like concrete underneath. And many of the weeds send down roots through the fabric. I've put in lots of garden space all over a half acre lot over the last 1.5 years that was an abandoned field before they built the house. This place is just one big invitation for weeds, yet I have no weed problem. Last year, I collected huge amounts of leaves from all around my neighborhood, ground them up, and covered thickly all the areas I wanted as garden. In the most weed prone areas, I put down a thick layer of newspaper before the leaves. In areas where I was putting in vegetable crops, I dug the ground up leaves into the soil several months before planting, and then mulched heavily again after everything was up and growing well. The thick layer of organic mulch keeps most weeds from sprouting. Weed seeds that try to take hold from the top never get a hold and are easily lifted. As the soil is being improved, it becomes far easier to pull out anything, but the truth is that I just don't have many. On a day in, day out basis, I never need to spend time with a focus on weeding. I do walk through though, when planting new things, to harvest, or just to enjoy. When I do, I pull up anything I see when little. Sometime - not very often - I'll take a quick walk through everything with a little pointy hoe I have to take out anything I see. The whole garden can be managed in minutes, and that is only every week or more. Nothing about it resembles a chore, and I remember those times weeding for my mom or grandad when it was. I don't spend a lot of time weeding because it is not something I like to do. I also don't like to see any garden filled with weeds. So I just set up in such a way as to make it so I don't have weeds.

  • Kimmsr
    9 years ago
    last modified: 9 years ago

    The "weed" barrier fabrics might help keep some of the unwanted plants that grow in the soil from coming up, but it will not stop all of them and some of the more aggressive plants will simply root in the fabric and continue growing. That fabric will not stop "weeds" that grow from seeds that are blown into or dropped onto the mulch by the wind or birds, however.
    Newspaper or cardboard will do the same thing as that fabric for a lot less money since they are available for free.

  • wrkendall
    9 years ago
    last modified: 9 years ago

    I don't use any kind of barrier. An even delivery of water and nutrients is key. Mulch is the best to suppress weeds. It also allows for even delivery of water. Depending on how coarse the mulch is as to how thick it is spread. So coarse = thick and fine = thin.

  • gcotterl
    Original Author
    9 years ago
    last modified: 9 years ago

    For coarse mulch, how many inches is "thick"?
    For fine mulch, how many inches is "thin"?

  • Kimmsr
    9 years ago
    last modified: 9 years ago

    Mulches need to be thick enough to block sunlight from reaching those unwanted plants. 3 inch bark nuggets could have enough space at 3 inches thick to allow enough sunlight to reach them while an inch of a finely ground bark might stop any sunlight from reaching the soil.
    How thick the mulch you use needs to be depends on many factors and while mulches can help suppress unwanted plant growth there are some plants (Quack
    grass for one) that simply will not be deterred.

  • Tiffany, purpleinopp Z8b Opp, AL
    9 years ago

    Landscape fabric doesn't do any of the things it claims it can/will, and eventually causes more harm than good. It will hinder desirable plants in various ways, and weeds can/will grow on top of it just fine.

    Putting cardboard under mulch is a much more effective method, which will smother existing weeds, then decompose (adding some nutrients to the soil,) doesn't hinder growth of desirable plants, quite the opposite. To maintain, add more mulch as the old decomposes.

    Once you gain control of the weeds by killing the existing ones, control is not difficult to maintain.

    I've been using leaves as mulch my whole life, first in OH, now in AL. Totally agree, different leaves behave differently as mulch, even within a genus.

    Not all oak leaves are the same. If they are totally flat, they seem to mat worse than the bigger ones with some curl to them. One general fact about any oak leaves is that they do take longer to decompose than most other leaves, mostly carbon, little nitrogen.

    This is much more noticeable when gardening a "new" patch of ground, recently reclaimed from lawn, or otherwise very infertile ground. Used alone in a new bed like this, they can cause some chlorosis and slow growth. Not a terrible concern if you're a long-term-goal gardener, planting shrubs and perennials. Something you'd probably want to address with some added nitrogen in the spring if using annuals, or just impatient in general. (More below.) But after a year or more, assuming you have been adding enough organic matter periodically, so that there is a decent amount of microbial life and decomposers like worms in the soil, oak leaves start decomposing much more quickly.

    Large amounts/percentage of walnut leaves can create problems for plants that are sensitive to juglone.

    If leaves aren't either walnut or especially resistant to decomposing quickly like oak, and there are worms and/or smaller life forms from the decomposition crew, a couple feet of leaves will likely disappear over the course of winter. Yes, I meant to say feet, not inches. This is how mother nature does it in the forest, nobody rakes in there, and leaves disappear. The ground ends up being dark, spongy, full of healthy and fertile humus and microbial life. The same thing can happen in even the most modestly sized garden beds.

    Matting and shedding water is a super way to zone cheat/push, keeping the ground temp from moderating too much, possibly preventing ground from freezing along the north/south border zones (Z6/7,) and being too soggy for marginally hardy plants regardless of the zone one is trying to push. A bit too cold + dry = possible survival. A bit too cold + wet = usually death via rotting. Should one find a mat of leaves in the spring, they can be fluffed, raked, possibly moved... and augmented with high-nitrogen sources such as grass from mower bag, kitchen scraps, anything with much more nitrogen than carbon.

    Leaves are only one great source of organic...

  • queen_gardener
    9 years ago
    last modified: 9 years ago

    Lol, I have posted about this before!!!!
    DO NOT USE WEED FABRIC!!!!
    I had/have both the plasticy woven type and the plastic trash bag type stuff. I did not put it down, I know it is pointless and futile, it was here at this new house.
    I had to pull and rip it up, and I have another couple beds to go - it was back-breaking work to rip up years and years worth of mulch and dirt. Weeds DID put down roots through the fabric, it was insane. Smaller weeds eeked out an existance on top of the fabric in the mulch, the weed barrier strangled the plants and shrubs - don't do it, just don't. Nothing was getting water under that stuff - not even after torrential rain. I was surprised how dry it was under the stuff. It was killing a knock-out rose, and it is still killing an azalea because for that bed, I'm going to have to dig up EVERYTHING in that bed, rip up the weed barrier, then replant.
    It decomposes, too.
    In addition to no water getting through, no new nutrients are being added to the soil. I ripped it up and found straight clay under it. Right next to it, in a bed that did not have the barrier stuff, the dirt was rich and black for several inches before it tapered off into clay. I know because I had to dig up a huge orange daylily patch that was next to the weed barrier bed, and the daylilies were trying to conquer the weed barrier area to no avail. They were stretching their roots and runners for over a foot trying to find an area to pop up. So the weed barrier was successful in trapping the orange tyrants, I mean, daylilies. But I had honeysuckle seedlings the width of a pencil that had pierced the barrier and were thriving.
    It was almost an instant turn-around for the knock-out rose - once it was able to get to more water, it looked 100 times better. I am hoping the azalea can hold out this winter. I discovered it and other plants and shrubs have been sending roots up over the fabric for years, trying to get more water. Some of the roots are substantial in size. I hope it doesn't kill the pine tree it is near, I'm sure some of those roots are the pine's, since they are usually shallow and long.

    So that's my story! I've read gardening books with personal stories of the weed fabric not working for the author. Just observing the stuff in parking lots and parks was enough for me. It doesn't work; you will just have to pull the weeds. If you don't let them go to seed, it's much easier! A bi-weekly pull of about 10 minutes should do it for most yards, I would think. That's what I've read! That's what I do; course, I'm not weed-free, but I have them pretty much under control. I try to stay on top of them.

  • Kimmsr
    9 years ago
    last modified: 9 years ago

    Cardboard, and newspaper, or a good thick shredded leaf mulch does not smother unwanted plant growth, they deprive those plants of the sunlight they need to grow so they die.
    Seeds from unwanted plants are put in gardens from many sources, birds, wandering animals, on the wind, so there is no barrier that will ever completely stop unwanted (weed) growth. Diligence in keeping those unwanted plants from growing will always be needed.