I'm researching putting a worm tube in my fruit-tree orchard as per this article but before I do so I'm trying to find out what radius the red wrigglers (the worm type I plan on using) will travel from the tube to calculate if nearby trees will receive any benefit from it.
Does anybody know the radius from the tube that red wrigglers will travel and spread their castings? (I'm guessing that the real question that I'm trying to get an answer to is: "Where does the worm tube need to be (proximity) for a fruit-tree to derive benefit from it?")