Earthworms have inhabited this planet for millions of years acting as a natural control to other insects and micro-organisms. They are not only good for the soil, but their very existence indicates that the soil is healthy. If you find no earthworms in your soil, you literally may not have healthy soil.
If you're into lawn care diy (do it yourself) tasks and are fed up with using artificial chemical plant foods and poisons to card for your yard and lawn, maybe you should take a look at one of nature's oldest and most enduring soil conditioners - earthworms.
One of the most important things that earthworms do for your soil is to aerate it. Soil aeration is important for the root systems of most plants. If your soil is too compact, water and foods will have difficulty reaching the root systems of your grass or other plants and will lead to them starving or traveling to the surface, which is not good. Aeration has a plethora of benefits to the soil. It helps to reduce and eliminate thatching. It reduces water runoff and improves soil drainage. Aeration helps to loosen compacted soil, especially soil that has a heavy percentage of clay, allowing the soil to "breathe."
Earthworms are nocturnal creatures and you won't normally see them in the daylight hours. They don't like the sunlight, probably from centuries of experience of being used as breakfast food by early morning birds. They love the dark and that is where you'll most likely find them on the surface. They also seek the surface after long periods of rain where they may come to the surface for air.
If you're just itching want to drive all of your earthworms to your neighbor's lawn, then use a chemical fertilizer that has a high percentage of nitrogen. Large amounts of nitrogen tend to make the soil acidic which earthworms do not like. If the soil becomes too acidic, your friendly earthworms will seek greener pastures somewhere else
On the other hand, if you desire to help your earthworm friends, leave your lawn clippings on the lawn when you cut it. The grass clippings contain natural levels of nitrogen, which is good for the soil. In addition, lawn clippings are a good source of food for earthworms.
Trifluralin is an active ingredient in many chemical fertilizers. Trifluralin is a suspected carcinogen which the EPA put under special review in the early eighties because of the presence of a contaminant that had been shown to cause tumors in animals. If you use chemical fertilizers on your soil, you are possibly putting the health of your lawn's earthworms in danger.
Eliminating poisons has other benefits as well. Domesticated dogs and cats often chew on grass, dandelions, and other plants in the garden. If the lawn and plants have been treated with pesticides, your pets are also eating pesticides. In the best case, they will not be harmed. But depending on the levels of pesticides used, they could end up with an upset stomach or worse, they could be seriously poisoned. The same applies to your kids if they play on the lawn and put things in their mouth as young kids will often do.
With these facts in mind, you have to ask yourself if using chemical fertilizers is worth it, even if they offer a much easier way of keeping your lawn looking good. If, however, you are willing to try natural means of lawn care, you may find that the lowly earthworm is your lawn's new best friend.