Smothering with something you need to remove later doesn't help suppress the sprouting of seeds (when the cover is removed) that are in the soil. Smothering with cardboard &/or a thick layer of organic material that can be left in place has been much more successful for me in regard to having less unwanted sprouts later and in regard to making an improvement to the soil, to increase fertility, tilth, moisture moderation in times of both too much & too little.

Thanks for your reply. You are right about seeds sprouting after the cover is removed. The tarps would be to kill the existing weeds for the interim while I decide if I want to fight the four-legged pests and stinkbugs again.

Putting an impervious cover lie a tarp over the planting bed to smother those "weeds" will work but it will also limit air and water exchange that the Soil Food Web needs, along with organic material, to live. Limiting air exchange could cause the soil to become anaerobic which would have bad effects on what you grow there later.

Better than a tarp, or plastic sheeting, would be newspaper or cardboard held in place with some organic (vegetative) material such as straw, shredded leaves, even grass clippings. The paper will do wat the tarp would do, prevent plants growing underneath from access to the sunlight they need to grow so they will die and will add organic matter to the soil and will also allow the soil to breath and get water.

kimmq is kimmsr

Very good points about the anaerobic effect. I did try using cardboard pinned with landscape pins. Organic matter on top would work better. Maybe I'll shred leaves this fall and mix in old potting soil to use on top. Thanks for your input.

Agree, cardboard alone isn't an effective smother because it doesn't block all of the light and doesn't have enough weight. Sorry if I didn't make that more clear above, and TY Kim for adding more detail.

If you have rhizomatous grasses included in what you are trying to smother, using a shovel to go around the perimeter to sever all connections to the material under the smother can also help make a big difference in the successfulness of the smothering.