Rye grass roots

If you're worried you can burn them and return the ash to the plot. They do dry out quite quickly on warm windy days though

You can put the lot in a big tub of water to kill them off but it takes about 3 weeks or more to stop them growing and it stinks to high heaven, but then you can add them to the compost bin sure that they're dead.  I'd use the water too but not on my seedlings I hasten to add 

I may be being dim here, but rye grass can be sown as a green compost and dug back into into the plot, so surely there would be no problem just putting it straight into the compost.  Wicken grass (aka twitch, couch and cutch grass) is a different prospect, re-growing from just a bit of root, and best put in the green bin for the council or burnt.

I was just thinking that myself. When you turn under the ryegrass, give it at least 3-4 weeks to breakdown before planting (which means turning it under a month before you expect to plant).

If couch is on the plot it's easier to dispose of there rather than cart it home for the green bin      I like to burn couch rhizomes - such a satisfying sizzle 

I meant to say couch grass.  It was (another) senior moment

I have those moments, granjan, by the bucketful !!!!   Just keep pulling it out when you see it and you will get a cleaner plot ... ours was riddled when we first started the year before last, now we only see the odd bit ... mainly sprouting up between the pavers we've used as pathways!   (gran)jeanieblue !!!

Some of the worse ones on my plot are amongst the raspberries.  They were so bad that I dug some of the canes up and cleaned them up before replanting last autumn.  The only trouble is that the couch seems to have been replaced with marestail    I can't win!