[Potty Plotty Lotty]

I have a narrow bed adjacent to my neighbours plot which is riddled with couch. He does clear it periodically so it's not a couch meadow but just random bits here and there. 

Do you have any suggestion of what physical barrier to use, how deep I need to bury it and how much to leave exposed above the soil on order to stop the couch spreading into my bed.

Suggestions I've come across through the years have been:

-empty compost bags
-weed suppressant membrane (I have some spare)
-growing turnips

but I haven't yet tried any of these properly.

I'd love to use this space a bit more effectively and maybe get some rhubarb crowns established in the bed but I'm keen to keep the couch out a bit more than I've managed through the years.

This is my next "project" so not adverse to splashing out a bit on materials if needed.

[Blewit]

Couch has very strong, sharp growing tips so you might find weed membrane or compost sacks lack the strength needed to withstand a 90 degree attack. In the past I used old perspex panels (freebie) but they're not easy to get hold of.
On our current plot we planted Mexican Marigold (Tagetes Minuta) which worked well but don't be fooled by the Latin name - it grows to about five feet tall.

PS like turnips it's exudates from the roots of Mex Marigold that deters couch.

[Gardener and Rabbit]

My father-in-law used old roofing slates to make a physical barrier to roots along an unkept field boundary, and they definitely helped to keep the weeds out. Set long-edge down they must have been something like 12inches deep. They'd been set almost level with the soil surface, but anything that came over them wasn't rooted at that point so was easy to deal with.

G&R

[cc]

"Do you have any suggestion of what physical barrier to use,"
Roundup!

[Potty Plotty Lotty]

"Do you have any suggestion of what physical barrier to use,"
Roundup!

Not quite the physical barrier I was thinking of 

While I'm not adverse to a little careful use of roundup it's not a permanent solution to the couch coming through unless I nuked his whole plot 

Thanks for the suggestions.

[Goosegirl]

I'd use empty plastic compost bags and cut them along one side and also the bottom, then dig a trench as deep as your maximum depth of bag, then place the bag in the trench and cover it with the trench soil so you can just see the top of the bag edge. This should give you a decent enough depth of barrier to prevent most of the nasty couch sofa encroaching on your plot.

[Enfield Glen]

Look out for someone having a new rook and see if you can get some free roof tiles that they take off, wont be 100% fool proof but would be longer lasting and greener than plastic

[snowdrops]

Could you make a sort of ditch between you & neighbour that you could then stop the couch crossing by either pulling it,weed killing or hoeing?

[Potty Plotty Lotty]

Could you make a sort of ditch between you & neighbour that you could then stop the couch crossing by either pulling it,weed killing or hoeing?

It's quite a narrow bed so I'm reluctant to lose any further space.

I've think I'm going to go for some Corrapol PVC sheet sunk into the group. It will also give the plant some protection from the wind and maybe the weed seeds that blow in from next door.

[Odders]

Buy a roll of damp proof membrane (DPM)

I used this one: https://www.screwfix.com/p/capital-valley-plastics-ltd-damp-proof-course-black-30m-x-450mm/59882

Bury it so there's 5cm sticking up & 40cm deep & it'll stop anything except marestail.

[Odders]

Could you make a sort of ditch between you & neighbour that you could then stop the couch crossing by either pulling it,weed killing or hoeing?

It's quite a narrow bed so I'm reluctant to lose any further space.

I've think I'm going to go for some Corrapol PVC sheet sunk into the group. It will also give the plant some protection from the wind and maybe the weed seeds that blow in from next door.

Oh & regarding weed seeds blowing in: I fastened 1m high debris netting to the fences on my plot (apart from the N facing one which is 2m high so it got two lengths) & it's hugely reduced the number of thistles & dandelions whilst not blocking too much light.

[rowlandwells]

we always spray our allotment  boundaries every year with roundup because it keeps the weed rubbish round the fences clean all year but I'm a bit cross that a couple of  allotments near us haven't been cultivated basically they have gone back to nature so it looks like we mite possibly get the weed seed drifting across on our plot