Most garden centres sell it, so does Wilko. Weedkillers aren't cheap but a bottle of a Glysophate one is around £10 a bottle which is probably a litre of concentrate.

The product you are after is named 'Roundup' although there are other products that contain 'glyphosate '

This link will give you the background about it and how to use it!

http://www.roundup-garden.com/

Word of warning.......apply strictly as detailed on the packaging and personally I wouldn't use it this side of spring.

It is best used on the young growth that is produced in spring.

Roundup is the most commonly recognised trade name weedkiller using glyphosphate. It is readily available either as a concentrate or in one litre spray bottles from any garden centre and is not expensive.
As Teegee says, it works best on weeds in active growth but given relatively mild weather it might be worth giving them a spray now. Just don't let the spray get on any plants that you want to keep as it will certainly kill them, winter or spring!

Hi
I agree with the other comments but if it is for your new allotment then it will be very difficult to eradicate with weed killer and also a long process that will take a few seasons and a few gallons of the stuff. The best way I have found is to dig out as much as possible then cover the ground with black membrane/plastic this will stop any airborne seed from germinating and suppress the already existing weeds from growing then in spring when the ground warms up lift the cover and the weeds will start to grow give them a couple of treatments with weed killer and this will restrict the growth a little bit next summer and if repeated for a few years if lucky you may get on top of them. Unfortunately about 80/90% of work on an allotment is weeding especially when you first start. Also I would not compost any weeds that you dig up burn them
Steve

What stubborn weeds have you got JVT?

I've found roundup applied on a dry sunny day very effective on most weeds although some will need 2 or more applications. It is a bit late to apply it now but worth a try.

It is not at all effective on mares tail although it will slow it down a bit.

If you have the weed mares tail I'd get a new allotment.

There is something called Kibosh that will nuke it but it costs nearly £40 for half a litre of concentrate and even then you'll get some regrowth

A word about Round Up - its not environmentally friendly and it doesn't bio degrade, both claims the manufacturers made when they first marketed it, and which they have now had to withdraw from the packaging.

Glyphosate in its generic form is much safer - it does not contain some of the other ingredients found in Round Up, and its that combination of additives which cause the problem with Round Up. I recommend you buy generic glyphosate, and add a squirt of washing up liquid to the mix when you dilute it. It will be just as effective as Round Up, better for the environment, and better for your wallet.

That's good to learn Bamboo.

i have been buying concentrated glyphosate from my wholesale nursery supplies supplier and it's also quite a bit cheaper than Round up.

i hadn't though of adding washing up liquid which i guess is to make it stick better?

I used some on some kerria suckers a week ago and it has killed them, so if the mild weather continues, you might try using it and see if you get some good results

Yes, Anchorman, acts as a surfactant.

Is generic glyphospate readily available for ordinary mortal gardeners or do you have to be in the trade with an account. I would happily shift away from Roundup if I could get the alternative. I mean over-the-counter rather than mail order.

Wilkinsons sell their own labelled glyphosate, Bulbaholic. It is also marketed by Scotts as a concentrate called Tumbleweed, but that's more expensive.

Tumbleweed I have heard of, we don't have Wilkinsons here.

I get mine from a trade supplier but although I am trade they never ask for any ID. The place is in Wisbech ,Cambridgeshire.

If anyone wants the name ask me on private mail on here

I have found the ready to use stuff sold by Lidl and Aldi is very effective. None of the above is any good unless applied on a dry day when rain is not expected to fall. All the above mentioned are weed killers which travel down to the roots of the plants. Some weeds have roots which travel a long way and its unrealistic to think one application can go that far, which is why you need to re apply the weed killer. Maybe the allotment committee can source a cheap supply of glyphosate. NB don't store it in anything other than the original container and if using your own dilution make sure you empty it all and mark the sprayer with what you have used in case you or someone else uses it for spraying feed on to plants.

"unless applied on a dry day when rain is not expected to fall"

Certainly the weed killer must be applied in the dry but the moment it has dried (often in 10-15 minutes) it is then immune to rain

Thanks Anchorman I did not know that.