Allan, I have been experimenting with vinegar for about a year but only for the Canada thistle. The ARS article indicates vinegar has been field tested on common lamb's-quarters, giant foxtail, velvetleaf, smooth pigweed and Canada thistle.
There are several weeds that infest our gardens: milkweed and thistle are the most persistent. We deal with burdock and others by chopping off the young plants. I was not familiar with thistle and milkweed (which were not in our previous garden in the city) until they got established in our grape plantings and asparagus beds. We had almost given up on one asparagus bed and have started a new one. Now I find a few have cropped up in the new bed too. My approach has been to dig the weeds where they are not wanted. I have had plenty of exercise, as I often have to dig to 3 feet down to get the last bit of roots. The milkweed is under control this way. I have not been winning the war over the thistle. There are large holes where I have been repeatedly digging. I've done the black plastic mulch with limited success. I cut them to the ground, and I cut and bag any flowerheads before they mature. Cultivation of the ground reduces the population but there are areas which are not cultivated. I am starting to apply lime and fructose to improve the fertility of the soil which will eventually (I hope) make it unfavorable for the thistle to grow. (There is an old posting on lime and molasses for weed control in this forum.) I am also waiting for the rain to stop to apply BD500 for the first time. Therefore, I am not relying only on the vinegar. It sure is nice to have something that works if you don't want to dig up the driveway, the lawn, perennial border and other areas. Use an ordinary 1 liter spray bottle. After each use, empty the bottle or remove the sprayer portion and rinse it in order to prolong its life. Wearing gloves and a dust mask (to prevent inhaling acid mist), spray the leaves. Adjust the size of the spray to fine, and hold the sprayer close to the weed.you are targeting. I do not suggest broadcasting it over a large area, since you will have to adjust the pH of the soil with more lime later on. Typically, I pull or cut weeds around the weed I am targeting to minimize the amount of vinergar I use. I have also removed the lower leaves of the thistle before I spray. You will not notice anything immediately. Do not be discouraged. When you go back an hour or so later, you will be pleased to find that the leaves are browning. Wait a few hours more and they would be looking dead. If you didn't have good coverage, parts of the leaves would remain green. Re-apply. The weeds I treated two weeks ago have not re-srouted. Last year, I was using a large syringe to apply 5% vinegar on the stems. Without the right kind of needle, it is tedious. The needle has to be large or else it gets clogged. I finally got a veterinary type needle. I had limited success. I will be trying it again with 20% vinegar. Digging an asparagus bed does not work as the thistle roots are intertwined and indistinguishable from the asparagus roots. This is what I have done: Where there is a thistle next to the asparagus, I shield the asparagus stems with plastic. I also lay some plastic under the thistle, then carefully spray the minimum amount of vinegar on the thistle. Remove the plastic. So far the asparagus plants have not shown any damage. I would wait a while before I add lime to the area. Virginia ----- Original Message ----- From: "Allan Balliett" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, June 16, 2002 7:23 AM Subject: Vinegar > Virginia - > > Can you give more information on how you use the vinegar, what the > results have been? How effective is it? How long does it take to > work? (I ask because I'm looking at a lot of electric fence line to > clear this week. It would be nice to have a 'no leaf zone' under the > bottom wire for a while!) > > Thanks > > -Allan > >
