Hi Benny and welcome. If you look this web site up it should help you. www.allotment.org.uk/articles/weeds_and_what_to_do.php Good luck
http://www.dgsgardening.btinternet.co.uk/horsetail.htm gives you sime information about it, and why it's so difficult to get rid of. It mentions weed-killers, and you may not want to use them, and Hornbeam will certainly tell you exactly why he feels you shouldn't :D So here's what the garden organic people have to say about weeding in general - I think a combination of these approaches would be best. I have some horse-tail, and it's coming up through monoblock, which is a real nuisance as I can't get at the roots, but being persistent should eventually get rid of it as no plant can survive constantly being deprived of its leaves,as it then can't photosynthsize, and will eventually die. Hope this helps http://www.gardenorganic.org.uk/pdfs/international_programme/Weed.pdf
Horsetail aka marestail is a wonderful plant and one of the oldest land plants. Dinosaurs ate it and it is still here long after they became extinct. Just lop them with a hoe to control them. Once valued as pot cleaners and nicknamed "pewterwort" because the silica in them was a fine abrasive for polishing pewter candlesticks and other items. Enjoy them and ask yourself what harm they really do. Use weedkiller and they'll just laugh at you while you poison your allotment for everything else. :D
Whatever you do, don't compost it. When you weed an area with horsetail/marestail, make sure all of the weeds from that area go out to the rubbish bin. And don't transfer plants from an infested area to another area - you'll also transfer the weed. We have been fighting it in two front borders - and after 6 or 7 years of weeding it has been reduced to two small, very small, fingers crossed, areas. Persevere. Hornbeam, its true it isn't doing any real harm -but if it isn't the plant you want in that area, it is a weed.
Hello Benny, we also have horsetail in our bottom field. It likes moist soil and spreads like mad. I think I will have to get goats to chomp it down or something. Welcome to GC and good luck.
Quite agree Rumple. Sure - if it's not wanted then it can be seen as a weed. You can even try to get rid of it, but it'll get the best of you. Roots go down a long, long way. It sheds its tops so easily without harm (that's why its modern popular name is the Lego-plant) It laughs at chemical weed killers too and you would have to use gallons of the filthy stuff to get down to the roots. Sure, go ahead and soak your soil in poison if you really want to. Just cut it down every so often to weaken it. Roots should not go in compo bin, but tops can.
I have put this bit of research I did on it into my website; http://tinyurl.com/y776vs In practice I find hoeing the tops off the young shoots as they appear and increasing the pH of the soil helps. i.e. it seem to grow more prolific on acid soils. So applying lime to the area can help. Thats my advice for what it is worth,and I agree with the others it is very difficult weed to eradicate. We are talking years!!!