covering weeds

[b300y]

Hi all,
just wondered how long it would take for grass weeds etc to die off after covering them with black plastic sheeting?
thinking of doing the bottom half of the allotment, dont need the space that much to dig it all up but would like it if you understand haha

[Feral007]

Solarising with black plastic: 3/4 weeks in very hot summer weather. 8/10 weeks in the middle of winter.

What I've found is that if they are flat weeds and you are putting the plastic down flat then it takes less time - but if they are higher weeds and you have the plastic inches above the ground in spots then it doesn't heat up as well.

When solarising if you are doing it in hot summer weather and can get it really really hot under there it will kill the seed bank in the top ground as well.

Some people say to water the ground first then put down the plastic. I've done it wet and dry and found it worked well. I put tyres on the plastic to hold it well down.

Because we had some tall weeds we mowed the paddock to remove the tall seed heads, then put the plastic down. Worked well for us. But you then need to cover the bare ground or the first things to take over the ground and cover it will be weeds. If you use cardboard you can kill a lot of weeds as well. And leave the cardboard there and plant thru it, or put a raised bed on top of it. In a garden I'd use cardboard, out in the paddock plastic was more suitable, but we've the secondary weeds moving in problem now.

[Two_Sheds]

I don't like plastic, I use wet newspapers.

I've just lifted some that I put down in April, on a thick patch of couch grass. All the topgrowth is dead, and the roots are really easy to dig out now.


Incidentally, couch grass (and any weed) is easier to pull out when it's just about to flower. The roots seem to lose their grip on the soil.

[BertieFox]

There are weeds and then there are weeds. I once covered a whole swathe of ground containing horsetail thinking that if I left it in place long enough it would kill it off. I left it in place for two years, but when we removed the plastic there were still blanched shoots underneath trying to find a way through, and of course, it came back almost as strongly after another year once back in the light. Most other weeds, like couch grass, you can get under control, but you still need to dig or fork over as those roots will still be snaking down there into the subsoil.
But it's a great way to bring a piece of land into immediate use. Just cut down the weeds with a mower or strimmer, cover with plastic, and make a few small holes through into which you can plant courgettes or squashes or anything else that is strong growing. Then you can harvest something and still clear the ground while growing a useful crop.

[Feral007]

Two sheds I use plastic to solarise the african lovegrass in the paddock because it makes the weeds inspector a happy man It is meant to kill the seed bank in the ground, but frankly it also kills the good seed bank and the good organisms that live in the soil. But I have to do some things to keep the man off the property. Cardboard and paper are much better agreed.

[snakeshack]

I'm a big fan of cardboard/paper as well,it breaks down and can be dug in end of season to help improve the soil.
BTW nothing kills horsetail/marestail but constant removal its been around for 200 million years or more and even the dinosaurs couldn't stamp it out.........and boy could they stamp!