I was given a sprig off of a Wandering Jew and was instructed to allow it to root in water. It now has 1/4 inch roots growing out of it, and I have no idea how to continue it's healthy growth. What is the next step?
Yes, plant it in a pot (ordinary potting soil), keep moist and grow in warmth and bright light. Some wandering Jews are grown as annuals in flower beds in your area. I don't know what you type you have, but if it is one of those you can make more cuttings when it is larger and plant them out next spring.