Can I lay wood chip and weed membrane directly over thick grass

[DavidT64]

Hi - I am new to the forum (and allotments) so if I have posted in the wrong place I apologise.

I acquired a 250sqm allotment in the summer and have been battling with what I think is couch grass ever since. The plot was newly created on an area of wild grassland, the grass is very thick with large dense root clusters, and as a complete newbie I don't have a lawn mower (which I think would struggle anyway) or much other equipment. I have a cordless strimmer, which in fairness did pretty well at maintaining a 4mx25m strip on one side over summer, enough to get some potatoes in and work space.

As the months have gone by I have got a little disheartened as I haven't been able to grow much due to spending all my time tackling the grass.

As it is now winter I plan on covering a large proportion of the plot in prep for the new year. My plan was to cover 4 (2ft x 10ft) beds with weed membrane, then use the membrane with wood chip on top to mark out paths.

I hope this will significantly reduce the amount of grass that will need cutting in the new year. Is it possible to lay this directly over the grass, without the need to cut it first. As I was able to cut most of it over summer its perhaps only 1ft high, but due to the weather is currently mainly laying quite flat to the ground.

[Snoop Puss]

Hello and welcome.

It is miserable, isn't it? I was in a similar position when I first started. My veg patch is divided in two. On one side, I went down the herbicide path and applied glyphosate. It worked quite well on the grass, I have to say. But I didn't like doing it...

On the second part, I did what you're not supposed to do: it's an extremely large plot and a friend offered to come and turn it over with his tractor and plough. I left it all for a few days afterwards to dry out and then picked out all the roots I could find. The tractor plough left it in big clumps that were pretty easy (if tedious) to identify and remove. I still have some that pops up wherever it can, but nowhere near as bad as before. I would definitely not advise that you rotavate it, though, as a rotavator would chop it all up, making it difficult to remove all the bits, which would then regrow, leaving you with a worse problem than before.

Keeping it cut short is no solution, as it will keep growing and spreading. The problem with couch grass is that it regrows very readily, so you do have to kill it completely, by chemical or physical means or by digging out the roots.

Weed membrane over it to cut the light might work, but I think you'll find it will take a long time. Your best bet would be to mark out your beds and dig them over first and remove as much of the root matter as you can before covering it. Even several layers cardboard might do for starters, as weed membrane for such a large area could prove quite expensive.

I'm sure other people will have different views (especially about the use of herbicide). Good luck, whichever method you opt for.

[burnie]

Couch is a never ending struggle, I've been here for nearly 15 years and still I'm removing it. I ended up building raised beds on top of a double layer of membrane, with the added bonus I don't have to dig or indeed even bend down to garden. Now this is in my garden rather than a lottie, not sure if doing exactly the same will work for you.

[Cadalot]

I went slow and methodical and managed to beat the couch grass into submission, but I did clear the paths as well because if you don't it just comes back into the bed see my progress on the blog and here is the link to my advice re clearing an allotment plot Alans Allotment: Clearing a New Allotment

[DavidT64]

Thank you for the replies.

My concern with raised beds is the cost of compost, I think for an allotment this size it may bankrupt me though I have thought about it.

I did try to dig over some of the plot during the summer. However the clay like soil and the thick root make it extremely difficult.

I may go the route of half and half as suggested, digging over as much as I can while spraying and covering other sections. Whilst I understand some oppose to spraying I also want to get some enjoyment out of the lot whilst putting in the hard work needed to clear the other sections.

[Snoop Puss]

If you do decide to spray, don't cut the grass or other weeds short first. Maximum leaf/grass blade cover delivers maximum chemical to the roots. I have to say that even though they say it doesn't affect harvests, I felt my crops were not as good in the first year as I expected. This may have been down to my incompetence, but recent studies in the States have found that this is indeed the case.

Also, be very careful to take proper precautions when spraying. Good luck.

Cadalot gives some great advice on his blog.

I should add that I don't have raised beds with wooden sides either. What I have done is established where my beds are by measuring out and then raking the worst clods of earth to the sides to form a low earth wall (maybe only a few cm high). This works quite well for me: keeps the water, muck and fertiliser in and keeps my rows relatively straight.

Note that I am no expert, though...

[lolie]

Thank you for the replies.

My concern with raised beds is the cost of compost, I think for an allotment this size it may bankrupt me though I have thought about it.

Even if you're not going to do raised beds, you can still use some of the principles. I'm about to put a raised bed in my front yard (which is pure clay) and it contains a lot of couch and a fair bit of buffalo. I'm going to spray and then smother the heck out of it with cardboard.

I did think about using just weed membrane but the drainage is terrible due to the clay. I filled in a few holes in my yard with compost a couple of months back and the couch is growing like crazy in those. My new bed is going to be 18 inches deep, so I've decided to put about 6 inches of organic rubbish on top of the cardboard, then cover that with weed membrane before filling the top 12 inches with veggie mix and compost. That will create two barriers to the couch. It will grow through eventually but I can just hit the emerging shoots with a weed wand when it does.

[Kirk]

Although not liked by many but the most direct option is the spray with glyphosphate. Get a sprayer with a 2 foot spray thing so you keep the exit point low and go over the area. I found I had better results if I mixed it 1.5x as strong as recommended.

I left mine for things to die then used a propane burner on the dead stuff and after 2-3-4 weeks sprayed again whatever appeared above ground then. And left it again. Not much appeared after the second one. I then dug over the area.

If you have a clay soil then at the digging stage dig it over with several bags of compost next to you to add as you go. They will lighten/open the clay soil up a bit. You will want a fair number but they can be any inexpensive ones.

There seems no middle ground of getting rid of the stuff fast but nicely. Fast means killed with extreme prejudice (chemical warfare and a flame thrower can be classed as extreme prejudice I believe), nicely means a good period of time, and effort. If you want to grow this coming year (starts 3 to 4 months away now) in it then the couch has to go.

Membrane and wood chips will I suspect just make it go dormant ready to rise from the ashes immediatly you uncover the area. So in a way back to square 1.

[Mark_Riga]

Hello David,
One thick patch of couch I had, I cleared reasonably well with early potatoes. I roughly turned over ground 1 spit deep, grass and all just before planting, put in spuds by making a slit with a spade and pushing them through then earthed up as best I could. Then kept pulling out the grass as it grew till the potato plants were reasonably big and could fend for themselves. I harvested when the soil was dry and was able, with a fork to get out most of the roots like spaghetti. These were followed, after a few weeks during which I kept an eye out for any that I had missed, with autumn onions sets.

Another patch was more nettle, dock and thistle but some couch. There I again turned over roughly just a couple of weeks before planting, then hoed off new growth before planting out winter squash, courgette,sweetcorn and pumpkin. Had to hoe a couple of times before the squash etc covered the area and the sweetcorn struggled a bit to get above the squash plants but then apart from yanking out the odd nettle, I didn't need to do too much and got a good crop of courgettes, butternuts, nice green banana squash and some pumpkins. Some rats though were quite partial to the sweetcorn so not so much of that.

The patch is fertile though, on the left is a strip of nettles etc that I didn't get round to but you can see the smothering effect of the courgette and squash. These were planted along the fruit cage. The picture was taken 15th July this year and needed little attention after that apart from picking courgettes regularly and harvesting the squash at end of year. At the back of the picture you can see some squash leaves as it is climbing over the fence and up the corner of the fruit cage.

[4Shoes]

I tried the quick bed method for potatoes this year. In essence you measure out area 4 rows wide for the plot. From centre, measure out the area for potatoes 2 rows wide and cover with a layer of muck and lay potatoes on top. Cover with turf (face down) from down each side, then once potatoes are through, cover over with soil from down each side. Then weed, hoe etc as you would for potatoes. Worked a treat. You only have half the digging in year 1