Weed fabric

Do I have to remove the grass before putting down the weed fabric under the square foot frame?

From what I gather, and I hope you hear from someone more expert than myself, it depends on the grass. The very invasive types like Bermuda need as much removal as possible. If you have grass that is less invasive, it probably doesn't matter.

I have an area that I may convert and my plan was to spray all with Roundup, cover with weed cloth and go from there.

From what I understand, Roundup is quite toxic, so you may want to use something else.

Donna In Zone 10
Coastal Southern Calif.

I rented a sodcutter and my son cleared the area where he would be putting my 12" high raised beds. That eliminated the grass roots beforehand.

I understand you could put down several layers (8-10) of newspaper inside the beds first and they will, in time, disintegrate, but not before they have killed the grasses below.

I used weed barrier under a pathway in my flower garden, then covered that with a layer of sand and then a layer of white marble rocks.
Two years later the invasive grasses still came thru.
Maybe if its used under 8-10 inches of soil it would work better. It also, I'm sure, depends on the grasses you're trying to cover.

I thought most of the folks in Texas have to fight the terribly invasive and tenacious Bermuda grass. If that's the case, it's best to dig up your grass and use extra thick layers of cardboard, etc. on the ground, or, use a plywood bottom and raise it off the ground with bricks or blocks. (or make table tops!)

quiltbea wrote:I rented a sodcutter and my son cleared the area where he would be putting my 12" high raised beds.

I gotta hand it to you, Bea. You didn't follow Mel's advice of starting small! But you're having a great garden this year-good for you!

I removed the sod and did not use the weed barrier. So far so good no weeds are coming up from roots.

donnainzone10 wrote:From what I understand, Roundup is quite toxic, so you may want to use something else.

Donna In Zone 10
Coastal Southern Calif.

I realize that, but for bermuda I would use it. I do not have the strength to dig out the sod and bermuda only considers it a favor anyway - a chance to grow thicker next time. I do not use it regularly, but if I needed to have a weed free SFG over an aggressive weed or grass I would use it.

Chopper wrote:

donnainzone10 wrote:From what I understand, Roundup is quite toxic, so you may want to use something else.

Donna In Zone 10
Coastal Southern Calif.

I realize that, but for bermuda I would use it. I do not have the strength to dig out the sod and bermuda only considers it a favor anyway - a chance to grow thicker next time. I do not use it regularly, but if I needed to have a weed free SFG over an aggressive weed or grass I would use it.

+1

+1

I try to grow organically as much as possible, but if you can't make the box super deep to choke out the Bermuda and/or nut grass, you pretty much have to deep cut the sod or use Roundup to eliminate it.

Make sure you use only the Roundup that is a contact kill, not the stuff that is the long-lasting and has months of residual. I also re-spray 1-2 weeks later on anything that still has a hint of green to it. Then I wait another 1-2 weeks again before I actually start the bed. Even doing this hasn't eliminated ALL the Bermuda and nut grass. I still have to pull some. I didn't do the respray on the paths around the first 2 beds I did and 2 years later, I get stuff coming up through the weed barrier (even though I've resprayed the paths multiple times since then).

Bear in mind that I'm usually only treating the paths twice since my beds are all at least 12-16 inches deep (I needed to be able to sit on the edges and not have to sit "down" too far when I built the first 2 and I've just continued that more for visual effect than necessity). I spray the actual growing areas just once, then wait 1-2 weeks before covering to make sure there's nothing too noxious regrowing. The paths only get a relatively thin (3-4") of gravel on top of the weed barrier which is just seen as a mild challenge by nut grass especially.

Sharon (who feels rather guilty for using a nasty chemical, but just can't stand the thought of pulling that stupid Bermuda or nut grass out of the veggie or flower beds for the rest of her life).

Thanks for your input. You have given good advice which I find helpful. This is new to me and I am still setting up the frames and deciding where to place them. I will have six 4x4's and one 8x4 raised bed. More later.

Best wishes with your SFGs, Claire, and welcome! Such a very exciting time!

(And I'm jealous, too... you are going to have a much bigger set up than I have.)

Not much experience with SFG, but lots of combat-skills vs weeds, from when I did Koi pond building/landscaping.

Best way;

Dig out the grass about an inch deep, lay weedblock (commercial ...not the cheap plastic kind) & put recycled rubber matting under the area (comes in 18 x 18" squares). This will give you a slight border/lip around yr 4' x 4' SFG box.

"Cheapest" & easiest way:

Get a 4 x 4 piece of old carpet ..... preferably the long/shag/pile type, but even the gren indoor/outdoor stuff will work (drive by any new construction or renovation site & it's yours for the asking). Hose it off & let dry a day before using.
Flip the carpet over (pile side down), lay your weed block on top & install your box over it. As a bonus, the carpet will help level your box if the ground is uneven.

In the South, the grass runners are brutal ....so simply building something over the grass, or simply digging out where your going to build, simply isn't an option.
Chemical defoliants rarely stay put & rarely work very long.

I noticed that Menard's has different ounces in the weed fabric. 1.0 - 3.0 oz. the higher the ounce, the thicker it is. I am finally converting the remainer of my former row garden to square foot gardening and the kentucky bluegrass/weeds have taken over that area. I planned on scalping or possibly cutting it out. What ounce do you recommend I use? My other weed fabric was given to me (out of the packet) , so I don't know what ounce it was. Thanks!
Kim

I live in North Texas and just layed the weed cloth over the grass befor it started to green up. I had on my burmuda grass problems except at the edge where the grass grew between the bottom of the box and the weed cloth. I moved my garden this winter and I am making an 18" boarder around the garden to take care of that problem.

The 3oz should correspond to "commercial grade" (I've seen it marked both ways).

The commercial grade is easy to identify, as it typically has glass/synthetic rovers (threads) in it, as opposed to the molded/perforated plastic sheet.

The comercial grade typically looks like this (probably varies by manufacturer)......but it's my understanding that the reinforcing "thread" is what separates the grades of material.

For what it's worth, I have since pulled out all the gravel, it just never "settled" and became firm underfoot like I hoped it would. It was work to walk around my beds. I pulled up the weed cloth completely, except where it was under the beds. I tried to pull out what I could from underneath, but had to just cut it off at the margins.

I laid down a couple layers of cardboard, then put crushed pecan shell mulch down. It is much prettier, firmer and less slippery underfoot and is staying in place well. I have actually had less weed problems (so far) than I had with the weed cloth down. I did not respray with anything. I did pull up what I could of the nut grass that had easily penetrated the weed cloth. I have had to pull some weeds at the margins of the paths, but fairly minimal.

After I've gone through a summer with the cardboard/pecan shell mulch, I may have a different opinion, but so far, I'm liking it MUCH better than the weed cloth/gravel combo.