Hi Pauline 🙂
It may depend on where you are.
In the USA some people sell the “Alabama Jumpers” (Amynthas gracilis species).
But DO read up on them – some people believe they are invasive, but from what I understand its their “cousin” A.agrestis which is the problem one.
Here is a current article, from Cornell on the problem in the USA:
As to putting composting worms in the garden, there’s a few things you must do to make conditions right for them.
Here’s a link to some information I published recently:
Thanks very much for posting your question