Topic: More questions..black polythene and green manure

[emma h]

Not together ;D!

Where do I get black polythene? Do I just use bin bags or is there specific black polythene that should be used to cover up bits of the allotment

and

It will probably be another 2-3 months before I am doing major planting, so can I add anything to the soil or green manure it to improve it over the next few months or am I too late?

thanks
Emma x

[wardy]

the black sheet mulch is strong and porous so it lets rain through but doesn't allow weeds to grow.  you have to peg it down.  Pegs are made of wire and are available off the internet.  I got mine from the garden superstore.  You can lay pallets, water filled bottles, planks of wood, bricks etc on it to hold it down but the pegs do work very well.  There are several brand names like Formycil and Tenax and you can get it online via SmithnJones or Allplas (or Allplaz)  I get mine in 2 m widths.  You need to get the heavy weight stuff to make sure nothing grows through it. You can use it for paths too as it's tough enough to be walked on.  I have much of my plot covered over with it, and some of it has been there for over a year.  It blew off recently and I saw that the patch which has been covered up the longest is free of weeds.  I shall uncover that when weather picks up and once the lights hits it then I'll see what if, any weeds, germinate.  You can then replace the black placcy again for a bit longer.  You have to be patient but it saves digging and I have plenty of room, which I know many folks don't.

[supersprout]

If you don't want to spend any ppps, cardboard held down and covered as much as you can with anything heavy - bags of coffee grounds, old doors and spent hops, even soil. Won't last as long, but will give the weeds something to chew on and tire them out  :P
My plot has woven/porous ground cover with green squares for fallow bits and paths, held down with metal pegs, plus bags, doors etc. If you get good stuff, you will be able to re-use it so it works out economical. Sun, tempests and happy feet will quickly shred e.g. bin liners, and the wind will find any nooks and crannies not held down firmly.
My neighbour covered his whole plot with black plastic and threw a few bits of wood across thinking this would hold it down. Then came a few breezes, and the resulting black shreds have plagued everyone's lotties since  :o. I'm with wardy with the woven plastic, then you only buy it once and it does the job.

[Derekthefox]

A question Wardy on the most effective way to use the weed barrier. I would imagine that the fastest way to kill the weeds would be to allow them to germinate, then put sheeting down to kill them, then after about three weeks, lift the barrier to let more weeds germinate, and repeat ... the idea being that the weeds are allowed to put energy into germination and initial growth, then denied the light they need to continue ...

Is my reasoning correct, or do you just leave the sheeting down permanently ...

[Sprout]

Getting back to Emma's original question, The Organic Gardening Catelogue sells black plastic sheeting for this purpose but would prove expensive to cover a whole plot. I did get some cheap sheets from my local garden centre last year and these were rubbish. Like previous post, these have shredded and are now useless. I did get a roll from the OGC and this is much better - a lot thicker.

[amanda21]

I have about half my plot (approx 20yrd x 6yrd) that I would like to cover with black polythene and dig as I go along.  When is the best time to lay this down - I haven't done anything to this bit of ground but some of it has been cultivated - possibly last year - but the top half doesn't look like anything has been done to it for ages and is very uneven and covered in a grass (couch?).  How long will it take to kill the weeds off?

I was imagining just covering as much as I can and gradually pulling it back as I need more space.  I am just worried that come the warm wet summer the top end of my plot will be a very disheartening jungle if I just ignore it!

[Sprout]

I would think that any time of the year is ok. I now have parts of my plot covered which have already been dug over in the hope that it will stop any more weeds from appearing.
This same part was covered in couch grass last year and I left black plastic sheets over that from mid-summer until fairly recently to kill off the couch grass. It worked a treat but you do need to keep it on for a long time.
Love the cat picture.

[amanda21]

Thanks Sprout.  I can't see me getting anything dug up the 'rough end' for a good while - I would quite like a shed up there at some point.  Think I will visit the garden centre tomorow and get some off the roll. 

It seems quite expensive though so maybe I should prioritise and cover the worst bits first otherwise a piece 20x6 might not look so great on the Visa bill - still I'm sure OH will be impressed I can spend that amount and it NOT be on another pair of new boots! ;)

[tigglestiggles]

like that bit about the boots

my husband was quite impressed that I bought a wheelbarrow yesterday and not a new handbag!!

[bupster]

There's some porous stuff that b&q have for about a quid a metre. It's quite lightweight but seems to do the job and hasn't shredded yet.

[Melbourne12]

http://stores.ebay.co.uk/Supplies-Direct

This is where we get our black plastic mulch from.  It's very good quality, and the prices are as low as I've seen anywhere for that weight of fabric.

We used it on our raised beds after they were harvested and weeded at the end of last season, and the soil underneath is genuinely weed-free.  We've also used it as a permanent mulch for a strawberry bed.  We pegged it down with big staples made out of wire coathangers, and it hasn't shifted at all.  Magic.

[amanda21]

Brilliant thanks - was wondering what to use to keep it down as I have a real shortage of bricks and wood etc.  Does the wire not split it?

[Melbourne12]

Brilliant thanks - was wondering what to use to keep it down as I have a real shortage of bricks and wood etc.  Does the wire not split it?

No, because it's like a coarse woven fabric, you can push a wire through it with minimal damage.  Even cutting a cross or a hole to plant things through doesn't cause it to "run".  I don't suppose that it will last forever, but I'd have thought five years would be entirely practical.

[John_H]

Brilliant thanks - was wondering what to use to keep it down as I have a real shortage of bricks and wood etc.  Does the wire not split it?

I ran out of bricks. So I started making 'soil bags' instead , I just fill one carrier bag with soil, tie a knot in it and then put it in another carrier bag. These do slide off plastic sheeting if its not on level ground, but its great to have some weights with handles on them and you don't have to bend down all the time to move them around.

It can make parts of the plot look a bit like a landfill site, but if you get those nice green bags from Holland and Barrett then it will look a bit less of a mess.

When you have finished with the bags all you need to do is empty the soil out of them and put them in one another to take home for the rubbish - I think its easier than getting rid of surplus bricks.

[amanda21]

Right I have some black plastic - enough for the wild end of the plot.  Can I put it down whenever - ie while it is still as cold as it is or will I be trapping in the frost?  I'm not going to want to plant under it for a good while.

[Melbourne12]

Yes, it's going to be a pretty dry weekend, so it'll be a straightforward job.  Anything you can do in the way of getting rid of any tall weeds will be a help, since you'll want the black plastic to lie nice'n'flat.  You don't have to dig them out, just chopping them down will do.

As soon as we get a sunny day, the soil will warm up under the plastic, so don't worry about any current frost.

[stuffed]

Old carpet works well.  You can often find it thrown out for free.  It is quite heavy so just a bit of weighing down at edges. Water can get through. lasts ages. Just lift it occasionally to make sure the weeds don't manage to start getting through the weave, although this is not usually a problem. My parents have long used this method on their lotties. They used to have a very heavy clay soil on one so decided they would use the site as land to put pots on.  They covered the whole lot with carpet, really as something to walk on and just grew in loads of containers. They then found that all the weeds died under the carpet so have used it ever since on their other lottie.

[John_H]

Black plastic seems to warm the surface soil up quite a lot even after only a few days of rays.

I've just got hold of a nice bit of plastic which some builders abandoned and I only had it down a week before the dormant weed seeds started to germinate , grow and die underneath it. the way I figure it, the more weeds I can get to germinate and die off at this time of year the less competition there will be with what I sow later on.