Most websites advise to plant the corn seeds once we've finished having frost at night. Once the corn has grown several inches (advice seems to go from 4 to 8 inches), the plant the bean and squash seeds around the corn plants. As the corn grows, the squash and beans will grow around it.
Would love to hear comments from any one in the garden who has tried this--were you successful or not? How does it work in an urban setting like 6/15 green?