When to weed?
As eager as we are to try out a new toy, especially one that makes weeding fun, certain conditions must exist prior to pulling weeds. Naturally, we can force the tines into the hard ground and twist the tap root with force but it most certainly will shear the root rather than up-root it leaving a lot of it embedded in the soil. This defeats the purpose and should be avoided.
No weeding tool can extract the weed entirely in compacted soil, the root just isn't that strong. However, a good day after a soaking rain allows the tines to penetrate deeper which will allow more of the root to twist free.
Weeding Techniques - "Download Operator's Manual Here"
The secret to extracting a dandelion is to center the bottom plate of the Weed Zinger over the dandelion. One technique that is very effective is to lightly tap the top of the weed and see if the leaves deflect inwardly together. Once centered depress on the foot pedal and check to see if you are able to engage at least 3 "clicks" on the center shaft. The more clicks the more stored power is available to eject the weed. This also indicates that the ground is sufficiently moist and will make the job easier. If the ground is too firm you will not compress the spring fully. If the ground cover is too soft the bottom plate will sink into the ground and not engage enough.
Dandelions grow from a lengthy taproot that, when severed, can grow into multiple new plants. This taproot is one of the reasons dandelions receive such negative attention. A single, fleshy dandelion taproot can extend many feet into the ground with small, hairlike roots growing from the sides. The ability of these roots to grow downward to such great lengths makes them better able to compete with plants over water and nutrients. It also enables them to thrive in many different climates and conditions.
The deep taproot of dandelions makes removal from the garden difficult. When extracting dandelions, if at least four to five inches of the taproot aren't removed with the above-ground growth, new shoots will develop on the broken root segments and continue to flourish. One of the best removal methods is mechanically pulling the weeds when the soil is moist so more of the root can be removed without breaking. Monitor the area regularly and remove the dandelions when they are young before the root has a chance to extend too deep. The population of dandelions can be somewhat controlled by mowing or plucking flowers from the stalks before they go to seed.
It's Too Late Baby
If your yard looks like the yard in the picture above you cannot expect to mechanically remove every weed and expect the grass to out grow the weeds. It is not possible. The soil condition of this lawn is ideal for weeds and must be treated with herbicides to regain control. For those of you that are looking for a holistic and natural approach you have some options but all of them will require more time and money than you are probably willing to spend. Treat the lawn with a good herbicide, fertilize it and then when the weeds start to die off you can consider spot weeding. Don't buy a mechanical weeding tool if your yard looks like this. One hundred Zinger clad ninja school children in a controlled full frontal assault would only remove the visible weeds but the soil condition will only allow more weeds to take their place.
The taproot typicaly extends straight downward but that is not always the case. Finding the center of the plant is key to removing as much of the root system as possible. When the soil is moist, usually a full day after a soaking rain, there is less resistance to the twisting action of some of the more common weeding tools. Regardless of the device, no mechanical weeding tool can guarantee that 100% of the root is removed even in ideal conditions, this would require a massive hole.
Hole Size...Does it Matter?
So, for all of you homeowners that are diligently removing weeds leaving small holes in their place that will be filled back in in a few days...your welcome.There are some homeowners that have a concern for the size of the hole that a mechanical weed pulling device makes, aside from the temporary appearance it is actually a key step in eliminating the weeds that are attempting to repopulate your lawn. Every Spring and Fall diligent homeowners aerate their yards leaving freshly heaved plugs of soil on the surface of their lawn, this process is critical because it introduces oxygen to the roots. Many homeowners stop there and expect to see their lawns flourish and in most cases they do. However, the ideal scenario is to topdress the lawn with a thin coat of finely filtered composted soil. Most homeowners cannot afford such an expensive process but a very good alternative is to drag a long cane pole or the back of a rake over them to break them up. Even if they are left alone they will break-down with every rain and work their way back into the ground.