That will. By covering over what was growing there and denying those plants access to the sunlight they need to grow they will die off. Some of the roots, however, may take much longer to die and later new seeds will be deposited and new plants will grow in.

Do you have any grass? Or is it literally just weeds?

kimmsr, my fear is iff the roots don't die off, won't plant just return? I'm thinking in particular about creeping charlie.

cwrebel, it there's any grass left, it would be a miracle. My husband's approach to lawn maintenance is --- absolutely nothing. The problem is I have huge perennial beds and I'm tried of fighting with the weeds constantly encroaching my beds. Plus they make the entire area look crappy. So I've decided to take matters in hand.
Somthering seems like it might be the simplest, but I'm concerned that it won't really kill the more pernacious weeds. And I would prefer not to drench the entire lawn with Round-up or something even stonger.

Covering many plants, Crab Grass, Dandelions, Creeping Charlie, will kill off the top growth of these plants and because there is no more top growth to feed the roots they will, eventually, die. However, you may get more seeds from elsewhere, or possibly the seeds of these laying in your soil may find good germination times and grow more, but new, plants.
Keep in mind that having a lawn that is "weed" free is something that has been around only since about the 1950's, even though for some that is longer then a lifetime. Since then we have been using poisons that have an adverse affect on our world as well as on our human genes.

I had a similar problem in my back yard. I have three dogs and two kids and wanted to avoid herbicides. Smothering would be a good way to start. Kill off what is growing and deal with new sprouts as they come up. My best friend was the hula hoe, or stirrup hoe.My yard was 25% grass, 50% weeds, and 25% bare dirt. I used a sheet of plywood, then twice a week or so I would scrape up all the sprouts with the hoe. I watered regularly to encourage new sprouts and kept mowing them down with the hoe. After awhile my yard was 10% grass 10% weeds and 80% dirt. I sacrificed some bermuda in the process, but I did see results. That was two years ago. I dont have a big weed problem anymore since the bermuda chokes out everything in its path. Now I just mow the few weeds that do sprout up. Continuously cut they won't thrive and never grow long enough to go to seed. Now my lawn is about 85% grass, 5% weeds, and 10% bare ground. The bare ground is full of bermuda stolons, and by the end summer I hope to have complete coverage. You can do it!

" If I laid down cardboard and covered it with three inches of compost, would that kill everything off?"

It worked for me.

kimmsr, I'm well aware that 100% weed free is pretty much an impossibility. I have a large 30' by 10' perennial bed that was created via sheet composting and there are always unwanted plants things seeding in. I was just concerned that the original weeds would be able to still sprout via roots. In particular creeping charlie will return from roots if they are viable even if the the top growth is dead.

cwrebel, that sounds like a good plan of attack.

ken, that's very encouraging! What sort of weeds did you have prior to using the cardboard method? And how long did you leave it before replanting? How deep was your compost? did you just lay cardboard down or did you water the area first? Any advice in general?

a2zmom:
What sort of weeds did you have prior to using the cardboard method?

The ground was a stony clay, well compacted, lightly topped with construction debris. It had a loose scattering of dandelions, plantain, beaten down lawn grasses, and what ever else you would find in a failed lawn in central NY.

And how long did you leave it before replanting?

I tilled it partly to kill off the weeds, but mostly to loosen up the soil. The cardboard and maybe some newspaper went on top to make a light and mechanical barrier for whatever survived my initial attack or tried to sprout afterwards.

After that I brought in a couple of truckloads of sawdust, then more of manure. I mixed and dumped them. After that I tossed on lawn clippings or whatever scraps came my way. It all sat there for most of a growing season while I waited for it to break down. I think I planted after the weather cooled down in the Fall.

How deep was your compost?

Maybe three to six inches depending where. It didn't start out as compost though.

did you just lay cardboard down

Tilled first. If I didn't have a roto-tiller I would skip that step. Daikon radishes would also work to loosen the soil.

did you water the area first?

We get regular rain, I saw no reason to wet it. Nature handled that part fine without me. If it had dried out while it was working I might have had to step in so the herd didn't get too thirsty.

Any advice in general?

Mostly just patience. I got tired of no visible results at one point so I went around all the old compost areas in my yard and scooped up worms, partly done compost, rich soil that had once had compost, and brought buckets of it to the new area. I scooped out grooves in the sawdust/manure and buried streaks of it in hopes of inoculating microcritters into the new material, get them hopping. It seemed to work.

When covering creeping charlie to control it, how long to you leave it covered?? deb

Leave it covered until the roots are dead, about 6 to 8 weeks.

kimmq is kimmsr