To get worms to come out of the ground you can use a soapy water flush or vibration.
To use a soapy water flush to get worms to come out of the ground, mix 1 to 2 tablespoons of some liquid dish soap per gallon of water.
Then pour the mixture of water and dish soap over a small patch of damp bare earth.
The soap will irritate the worms and cause the worms to come to the surface very quickly.
Once the worms come to the surface after you pour the soapy water over the ground, collect the worms right away and then rinse the worms off with some water to prevent the soap from harming the worms.
To bring worms up from the ground with vibration also known as worm grunting, start by driving a wooden stake into the ground and then rub a flat piece of wood or metal against the wooden stake to create a rhythmic vibration.
The rhythmic vibration mimics a digging mole, which drives the worms above the surface of the ground.
You can also get worms from the ground by waiting until dark in most and damp conditions such as after a rain.
Then go outside with a flashlight that is covered with a red filter and then grab surfacing nightcrawlers by hand.
Or turn over the topsoil in moist compost piles, under some leaf litter or even simply leave a piece of cardboard laying flat on some damp grass to create a great and perfect habitat for worms where they can often be collected very easily.