Thistles

[Common_Clay]

What is the best thing to do with thistles?

I have an area covered with black ground cover and when I took it off to prepare the ground for potatoes I found lots of small thistles trying to grow. I dug down as far as I could without losing ones I wasn't digging at the time under a blanket of earth... about a foot to 1 1/2 feet down and took what I could of the roots out, but never managed to find the end of any of them.
  I then had to leave that part for a few weeks as I wasn't able to get to the allotment, but the other day when I went there were loads of little thistles again! What do other people do? I'd rather not spray with anything if I can help it, unless as a last resort.

Thanks.

[Common_Clay]

[delboy]

The plot next to mine has been vacant for over 7 years and has become thistle heaven Now a couple has taken it over and has been a-digging down a spit deep, which has unearthed the thistle roots and divided them up.

I do believe they are in for a nasty surprise when all the new growth gets going...

Along with marestail/horsetail and horseradish(they have all of these!)thistles are hard to reduce markedly without deep digging and then 2 or 3 redigs, pulling out all the root parts found as you go.

Although I have mainly kept to the dig diddley dig approach, if faced with the triumvirate of weeds I would use weedkillers like ammonium sulphamate

[supersprout]

I used a dose of systemic weedkiller - once - on a really thistly/docky patch in May last year (before they flowered/seeded), waited a month for the weeds to die back, then covered the area in black plastic til the start of this year. I did plant through the black plastic and get winter crops. This seems to have done the trick.

[Common_Clay]

Thank you!

Can I use a weed killer like that on individual thistle plants in between potatoes, or is this not a safe bet at all? And what is paraquat? Thanks.

[supersprout]

Added later:
Gentle reader, please note that all references to 'paraquat' should read 'glysophate'. See Jerry's post - I got the wrong word in my head. Apologies for being confused :-[

It would be ideal, because paraquat only kills the plant whose foliage it touches. I use a squirty bottle for the odd perennial weed that's too close to tender plants to dig. You will find it in e.g. Roundup and Tumbleweed.
It goes inert as soon as it touches the soil so is good where you don't want to kill wildlife or pets.
NB One major consideration: Paraquat is lethal to humans if swallowed, so keep anything you use for it away from food handling tools. I use a seperate sprayer for paraquat only, wear disposable gloves to apply and throw them away.

[Common_Clay]

Thanks supersprout, interesting site... but it does say it doesn't kill the roots, only the green foliage and that's where it stops, so may as well just cut them off? Confused now! :)

[supersprout]

It goes into the leaves and is taken deep down into the roots and kills them. The leaves will stay green for about two weeks before they start to go brown, but the weedkiller is doing its secret work :'(. That's why it's best applied when the weed is putting on a growth spurt so the plant gets them around its system (hence, systemic), I find May is good.

[Common_Clay]

That's what I thought systemic was too, lol, but on the paraquat site it says:

'Paraquat contributes to the reduction of soil erosion by wind or rain because paraquat only affects the aerial (above ground) parts of weeds and does not kill root structures.'

Am I being stupid?  ???

[supersprout]

It works, honest ::) Perhaps it means that the dead roots stay in and keep the soil together (I certainly find some as I go along, dead as doornails)? Beats me!  ???

[sandersj89]

I dont believe roundup or tumble weed contain paraquat, their active ingredient is glyphosate which is a Monsanto product. Paraquat was a Zeneca (ICI) product until the patent expired a few years ago though they are still the main producer.

Paraquat is more normally a commercial product but it is found in weedol, pathclear  and Gramoxone

I dont believe it to be systemic unlike glyphosphate and it is classed as a contact herbicide.

HTH

Jerry

[supersprout]

Oh b***cks, I certainly meant glysophate and NOT paraquat, I am so sorry to have got confused C_C! :-[ :-[ :-[ Thanks jerry, glad you are here to clear it up (and thank you for being gentle) ;) Just shows when I last looked at the labels, I still called it paraquat but NOT ANY MORE :-X

[Common_Clay]

LOL, right, I've got some roundup and tumble weed somewhere around... I was thinking of discarding it as I was heavily scoffed at the allotment trading shed when I bought it! Might work for this though... If it takes a couple of weeks to work I don't really have time to wait for it before preparing the ground (again!) for potatoes... If I just pull them out again as far as possible, plant the pots and wait for them to shoot again before spraying, would that work? Or by that time will the pots also be shooting?

It's complicated, this gardening game, int it?

[supersprout]

Sure is C_C ??? But that's what makes it so much fun, there's never 'one right way' to do things is there? Options ...
a) whacking a black plastic mulch over the area and planting spuds through
b) dig normally, remove what you can, and plant the spuds like you say. This should result in a satisfying crop of new weed seeds and perennial re-growth in a few weeks, for hoeing or spraying at your leisure

Like you I'd be reluctant to use weedkiller at the same time as planting because of the toxicity, though I know a lot of people do. But if I had a real problem with perennial weeds, I'd go be happy spraying a couple of weeks after planting, to take advantage of 'flushing' the new crop of weeds, but before the spud sprouts come through.

heavily scoffed at the allotment trading shed

Lucky you, having one! We don't even have an association - yet ::)

[Common_Clay]

Lucky you, having one! We don't even have an association - yet ::)

Yes, very lucky to have one... on a Sunday morning it's not uncommon to have jam tarts and whisky shoved my way, lol.
Why is there no association for yours? Is there nothing for the borough you're in?