No weed killer I know of will eradicate couch grass it is a case of dig, dig, dig and then dig some more... Even the tiniest bit of root left in the soil will grow again. Pre-emergent herbicide products are applied to soil or mulch and create a barrier to weed seed germination, not something I would want to use...

The best way to clear any ground of weeds is to fence it off put in a small shelter and add 2 young pigs. Fred.

Now that is advice I can agree with Fred! Just remember to feed the pigs...

If you have an acid soil, planting rhododendrons will kill off couch grass near them - not something I knew until I planted some in my own garden.

Improve and improve your soil year on year. The only way is to get the roots (rhizomes) out and that is so much easier if the soil is friable. So lots of compost and lime (if acid soil) or gypsum (neutral soil). Lots of nice double digging.
Couch loves compacted, heavy soil that it can really hold onto.
Herbicides might work but couch is first to reappear after treatment as the rhizomes are adventurous and move in from the surroundings. Black plastic mulches suppress it but couch survives years dormant in the dark - that's why it shouldn't go into a compost heap.

Agree, dig,dig and dig some more and then weed kill what grows afterwards.
I have just about cleared a section, 15 feet by 15 feet and filled 18 bags with couch roots.
The farmer would not lend us a piglet for a few weeks, we did ask.

Oink oink lol Owdboggy!

My very old "Potters cyclopaedia of botanical drugs and preparations" says you can use the roots for urinary problems, gout and rheumatism!
And an infusion of 1 oz in 1 pint boiling water in wineglass doses taken several times a day for feverishness etc. (It doesn't say what etc covers!)Apparently it tastes slightly sweet. So there you are - waste not want not!

Well another Web site also says it taste disgusting.
It is supposed to be edible, sold in Italy I am told.
Soak the roots in a bucket for a few weeks and it turns into fertiliser.

Use the wine glasses for wine after the 'dig, dig, dig' method

love the idea of pigs :O) but do not think there would be anything left to see in the garden. lol :O) Bit like when I had goats, lovely to see but boy do they eat stuff. lol. I am always battling with couch grass, it is just a matter of dig dig dig as the advice says above. It is a survivor a bit like a dandelion is too. Good luck with it. :O)

Excellent suggestion, Worthy! Then sweet of disgusting won't matter.