Best way to smother Couch Grass?

[Colin_M]

I have two long strips of couch grass on paths between beds on my allotment that I should have dealt with and have now grown quite long. The grass is around 12"-18" high with the usual network of roots.

I'd normally dig this out but the soil is rock hard and there are crops either side. A method which has worked well in the past is to cover in black plastic (Old H has also recommended this approach).
Can anyone advise whether it's best to:

a) Leave the grass uncut and put plastic straight on?
b) Cut the grass first?

I can see that the first would leave a greater amount of leaf area to lose water etc. If cutting stimulates the plant, the second might trigger something, but would cut off the food supply more quickly. Any recommendations? Any other steps you'd suggest?

Finally, although Roundup might work, I'd prefer to avoid this and I have rows of crops right next to the Couch.

[oldherbaceous]

Morning Colin, as long as it doesn't hold the black plastic up too much, and make it dangerous for walking on, i would leave it long.

I see you are up early giving this problem some thought.

[Johnboy]

Hi Colin,
You must cut this grass post haste to prevent it seeding. If it manages to seed you will have a lot more next year and probably on your growing area.
If you cut it and cover with HD Black Polythene it will certainly weaken the growth but I doubt that you will get rid of it. Remember that a Polythene path can be quite lethal when it is wet.
If you were to use Roundup applied from a watering can with a drizzle bar the droplets are too heavy to be windblown so your crops on either side would not be affected. This is probably the most effective method.
The drizzle bar need only be an inch or so off the ground. If you are going to use this method cut the grass down to prevent seeding to about 4" and push the grass down to the ground with the drizzle bar as you go.
JB.

[Johnboy]

Hi Colin,
As an after thought; if you use a watering can make sure that it is thoroughly washed out using a detergent prior to using it again for watering anything. I actually have a red watering can which is used solely for the purpose of applying Glyphosate and nothing else.
JB.

[richard p]

another method of applying the weedkiller is to soak a rag and wipe that along the path, the rag can be burnt when youve finished with it. dont forget to wear marigolds whist youre handling it.

[Colin_M]

Thanks to OH, JB and Richard for their suggestions.

I had a bit of a debate on the "cut" or "don't cut" angle. In the end, since the sun is blasting down here I decided to strim it and let the stumps dehydrate for a day before covering.

Thanks for your warning about slippery paths JB. As you can tell by my lack of attention to this area I don't use this path much, so plastic on it won't impair access too much. I also have a spray bottle of Roundup that offers a "foam" setting which doesn't spread or blow around as much - I may use this if the breeze drops.

[Geoff]

IMG_1920_R.jpg (83.7 KiB) Viewed 5759 times

[Johnboy]

Hi Geoff'
What did you say the other day about being a smart arse!!
JB.

[Geoff]

Sorry about that, I was walking down the garden to photograph the bees and had a mischievous thought.

[Compo]

Treat the couch more than once with the glyphosate Colin it is hardy stuff

CoMpO

[Tony Hague]

Having just dug a bed previously with couch grass (and the rest !), which had been left under black polythene for a year, I can say that the only thing that survived was horsetails. Otherwise, just bare earth.

[Colin_M]

Thanks for the suggestions everyone.

Geoff, my eyesight is going but is that concrete I can see in your photo? Could work, just need to get permission from the Allotment Commitee........!