If you have a healthy population of Earthworms in your garden you could easily have 250 per square metre.
What do worms do in the soil?
They can consume their own body weight per day in food and so this means that they are processing 90 kilos a year, and providing you with several centimetres of new topsoil.
They bring up rich minerals and nutrients from the subsoil and deposit them as castings on the surface making them readily available to our plants.
Physically as they burrow into the soil the channels they leave behind channels which aerates and drains the soil. If you have a good population of earthworms 5% of your soil will be made up of aerating earthworm burrows!
For more help with your worms please visit our Wiggly Wizard knowledge base here https://wiggly-wigglers-faq.malcolm.app/