vegetable patch management
removing couch grass
Couch is a very tough perennial weed that propagates itself by sending out runners under the soil. It grows very quickly in warm weather and loves soft, sandy or heavily mulched soils. It is very difficult to control as even the tiniest piece of stem left in a garden bed will quickly develop into a new plant. If left unchecked Couch grass will completely choke a garden bed.

Illustration of how couch grass spreads
Couch grass spreads itself by
sending runners underground.
Photo of couch grass in a vegetable patch
Couch grass in a vegetable garden.

The wrong way to try and remove couch grass

Incorrect ways to remove Couch grass.
The common mistake many gardeners make is to try and pull Couch directly out on the surface or to dig it in with a hoe.

As the Couch stems break off easily, trying to pull them out usually leaves much of the root system in the ground to regrow again. And turning them under with a hoe may in fact help spread it as each small piece of stem left in the soil will grow into a new plant. Unlike many weeds, disturbing the root system won’t greatly hinder Couch.

The good news is it is a fairly shallow rooted plant, so you don’t have to dig that deep to get below the plant’s root structure. And it does not seem to produce many seeds, so if you remove it completely from your beds it is relatively easy to keep out.

But it is vital that you remove every scrap of couch, otherwise it will quickly re-establish itself. There are two methods I know of to effectively remove Couch grass. They are :-

Hand digging

Use a trowel to help you loosen the roots then gently hand pull the clump out intact with slow steady pressure.
With care it is possible to remove Couch by hand, especially if you have soft or sandy soil. Start at the edge of the Couch patch and dig down below the root structure. Use a trowel to help you loosen the roots, then gently hand pull the clump out in one piece with slow steady pressure.

You will notice a runner stem attached to the clump. Follow the runner along digging and lifting as you go until you reach the next clump. Repeat the process until the bed is cleared. If the runner breaks then try to find it in the soil and continue the process. Sometimes there will be more than one runner coming from a clump but, however many runners there are, they must all be followed up. It is almost impossible to remove every scrap of Couch at the first digging, so it is vital that you check the beds every couple of weeks for at least two months after the first weeding. If any new shoots appear then remove them using the same method.

Smothering couch

Place a thick layer of newspaper and mulch on the top and sides of the section you want to remove the Couch from.
For larger areas it might be better to smother the Couch. Firstly dig a trench around the section you wish to remove the Couch from, making sure you have dug deep enough to sever all Couch runners.

Then cover the top and sides of the section with a thick layer of newspaper and top it off with a layer of straw mulch to a depth of at least ten centimetres. The key is to make sure no light gets to the Couch plants while making the layer of newspaper thick enough so no runners can push though it.

The plot must then be left until all the couch has died, usually around four months. By then the paper should be sufficiently rotted down so you can simply turn the whole lot over with a fork , but check to make sure the couch is totally dead before you do so! An alternative to straw and paper is to use cover the bed with a piece of old carpet or carpet underlay.