The root, the whole the root and nothing but the root...that is the question. Removing dandelions is easy, but making it so they can't grow back is a futile endeavor without the use of harsh chemicals. One anology that comes to mind is shoveling seaweed against the tide.
I spend a lot of time, energy and money trying to keep my yard clear of these pesky plants. I realize that they are edible and that they make darn good tea and are good in a salad. A dandelion is to me as a pimple is to a teen, nobody wants them all over the place...or the face.
I have often heard folks make claims that the only way to eliminate dandelions growing back is to remove all of the taproot. Really? You are going to remove a taproot that is 6" - 12" below the surface, usually in compacted soil with a device that extends 3-4"?
No, you are not going to remove all of the taproot. Even under ideal situations after a good rain and the soil is moist and loomy, you may remove most of it, but not all of it.
"Then why should I bother buying your weeding tool or any weeding tool that can't get all of the tap root out?", you might ask.
Why treat acne? To better understand what we are up against I direct your attention to the photo below.
The taproot in this case is about 10" long with several off-shoots. The longest tines in the industry are only about 4" long. For anyone out there that has attempted to pull an earthworm from the ground, how many of you have succeeded? If you cork-screw it out you might have better results, but what if the ground is hard and compacted? This is why we recommend only weeding when the soil is soft like after a good rain. Your chances of removing the root and the worm are much better. Even under ideal conditions you will not remove the entire root. The only way to improve your chances would be to get down on your hands and knees and dig it out...carefully.
Let us all agree that that is not going to happen. The yard would like like a mine field, your neighbors will peek through their window shades and you will still have dandelions at some point.
I am not suggesting that there is no solution. I personally have 2 acres in the country with neighbors on both sides of me with a sea of dandelions. There is a very clear line that defines our property with a dandelion fence.
So how do I do it? I have simply applied some of the techniques that others have posted over the years.I aeroate annually, apply herbicides and fertilizer in the spring and fall. The moment I see a dandelion I remove it with my handy Weed Zinger...me and my grand-daughters make a game of it. I mow my lawn to the recommended height and I make sure the soil remains healthy and watered. Dandelions due not flourish in healthy soil, they prefer drought-like conditions and lawns that are unhealthy and unkept. The secret is removing the weeds early before the taproot establishes itself.
If your lawn looks like the one above then you would be wise to "nuke it" first and then try removing weeds mechanically.
On the issue of using an upright mechanical weeding tool like the Weed Zinger, Weed Hound, Fiskars, Grand-Pas, Garden Weasle and any number of weeding tools. All of them will pull weeds. Some of them are better than others and all of them have merit but none of them will remove the entire taproot unless the soil is soft, moist and the tapproot is shallow. Did I mention that the Weed Zinger shoots the weed? Shameless plug...I know.
In summary, make your lawn undesirable to weeds like dandelions first, immediately remove them when they appear, cut your lawn to the recommended height, add fertilizers (melorganite is fantastic) often and only use herbicides when necessary. If you take these steps you can make your lawn look like the lawn in the picture below. The picture above is what my neighbors looks like. You decide.