blue tarps... weed control?

[sheeshshe]

I saw some blue tarps for cheap yesterday and I just got to thinking wondering if they can be used for weed control at all?

[rainbowgardener]

Sure. If you laid them down and pegged them tightly and left them for awhile it would kill the weeds and everything else under them. But no water or air would be getting through and by the time you were done, the soil under it would be dry and cracked with no earthworms or anything left.

People do the same thing with clear plastic (called solarizing). The benefit of that is that it holds heat, so the top layer of the ground heats up enough to kill the weed seeds. The tarp won't do that, so if you killed all the weeds with the tarp and then tilled that spot, you would have a new crop of weeds again instantly.

If you just want to smother weeds, you can do it better with layers of newspaper. The newspaper is more breathable, lets air and water through, and it eventually breaks down and feeds the soil. Lay down multiple layers of newspaper and put soil and compost on top of it.

[sheeshshe]

I usually do the newspaper, but never end up with enough newspaper to go around.

the tarp is a bad idea then. what about using it for where the black berry plants that I was trying to get rid of are? could I put a couple layers of the tarp over that and kill that off? or would it still grow back there?

[applestar]

I'd go with a heavy appliance corrugated cardboard. One layer may be enough. Go with two if you want to be sure, but that may not completely break down over the winter. You can cut X's in the cardboard in spring to plant. It's a good idea to water the area thoroughly first and layer some compost or composted manure/animal bedding -- as well as any other amendments you think you might need like rock phosphate or lime to adjust pH, etc. (this will depend on the kind of manure, if any, you use) -- underneath first.

This might be a good time -- some people update their appliances before the Thanksgiving/holiday season.

[stella1751]

A little known fact about those blue tarps is that they shred in the wind. I laid one down last fall to keep a new bed weed-free until I could return to it in the spring. (It also serves to discourage the dogs from doing their business in a new bed before I can get the sides constructed.) Over the winter, small sections of the tarp shredded, just the occasional patch. When I pulled up the tarp this spring, it took hours to pick up each tiny piece. They were all about 3 or 4" long by 1/8" wide. It took forever, and I'll bet I missed some.

[TZ -OH6]

I tried to smother lawn grass with a blue tarp a couple of years ago. Enough light was transmitted that the plants underneath didn't even turn yellow, so if you use one it would have to be tight to the ground to smother from lack of oxygen etc.

[sheeshshe]

thanks guys!! I wont waste my $ then

[Gary350]

I know a tarp will kill bermuda grass. I had a bermuda grass spot in the yard I covered it with a tarp for 2 weeks in the summer and it killed all the grass under the tarp. It gets very hot under the tarp in full sun I think the grass was cooked to death. Black plastic kills grass and weeds faster than a blue tarp in full sun.