Plain vinegar will kill any plant without adding anything else. But thistle is a very tough plant with deep roots that spread underground, and the vinegar will not kill the roots. So it will come back. You can keep killing it, making sure to get every bit of green that emerges, until it gives up the ghost. Without photosynthesis, it will have no way to keep growing. But the best way to get rid of it is probably to deeply soak the area with water, and using very tough garden gloves, try pulling it out along with as much as the root system as you can get. Thistle will grow back from bits of root left in the ground, so you have to keep on top of it. For some reason, people love the idea of mixing concoctions of various common things like soap, Epsom salts, salt, oil and vinegar, but it often just makes a mess or hurts the plants you're trying to save. You're right. If it sounds too good to be true, it probably is.

Just rinse it out a few times. I'm assuming you're using horticultural vinegar (or 20% acetic acid). If the sprayer is "empty" when you finish, there's maybe an ounce left. Dilute that 128 to 1 (2 gallons of water) and there's less than 0.2% acetic acid left. That shouldn't be enough to kill anything. You'll still smell the vinegar after a few rinses, but your nose is capable of picking up things in the part per million to part per billion range without any issue. You don't need to worry about a faint/moderate remaining odor of vinegar.

It would be helpful to have some more information. You're assuming you have to have weeds and use weed killers. You don't have to have weeds, so if you could answer some questions we could figure out why have have weeds to begin with. Where do you live? What kind of grass do you have? What weeds do you have (grassy or broadleaf)? How are you watering (how often and for how long)? How high/low are you mowing? When were the last 2 times you fertilized and what did you use? I absolutely agree with organics. If you're concerned about the water then you might be concerned about using Milorganite. Milorganite is semi-processed sewage from Milwaukee. I use alfalfa pellets (rabbit chow) because it is rather inexpensive for me. You might use soybean meal if that is less expensive. The application rate is 20 pounds per 1,000 square feet. You can use it as often as you want.

Teeka, As one of those reporters, I'm sorry you're disappointed in us. Honestly, I'm often disappointed in us too. But please be aware that the industry is undergoing a massive shake-out - different and much more catastrophic for us than the general economic recession. A higher percentage of newspaper reporters have lost their jobs in the past two years than in the auto industry. We're up there with the finance industry in terms of lay-offs, and for as much as some people hate the media, there's no question, at least we didn't cause this recession. In a few years, there probably won't be daily newspapers in several of our largest cities. The newspapers that are around now have far fewer reporters than they did a decade ago. And many of those reporters are being asked to do many more things than they used to do - post on blogs, shoot, edit and post videos, host chats, etc. Some of us are really trying hard to save the industry, in order to save journalism, so that people get the news they want and need, whether it be about industrial agriculture, political corruption in Washington, the war in Iraq or your local school board meeting. I'm hopeful that we'll find a way, but the business model is collapsing and no one has come up with a viable alternative yet. So we may not. Just my little defense of journalism. And gardenwebbers please be aware, your favorite local garden writers are especially vulnerable right now. If you read one you particularly enjoy or rely on, consider an email to let his or her bosses know. A lot of times, the bosses making these difficult decisions don't know what readers want or like. A vocal following can help save a job. Ok. I'll stop. (And I'm not a garden writer. I'm a legal affairs writer and sometimes war correspondent... so there's very little anyone here can do to save my job when and if it comes up on the chopping block. It would be unethical for me to post something like the above if it would have helped me personally. I post only in hopes of helping people understand what we're going through, and how serious it truly is.) Susannah