I think if you try to trellis bush beans you will see them get to about a foot off the ground, and thats about it. Im wondering if your thinking about pole beans?

In the south we grow pole butterbeans. This is my first year with sfg, I plan to trellis my beans tomorrow. In a large garden you will have a post in the ground, another one maybe 10 foot away and a wire top and bottom between the poles with string going up and down wrapped around the wire. The beans will climb up the string, the vine will go as far as the string will allow. I am still thinking as far as the sfg goes.

Nope. Bush beans don't need it. Pole beans would.

Bush green beans in July (planted end of May/early June).
Bush yellow beans are at the other end of the bed.

Yellow bush beans in August:

Hope this helps.

Here is a link that might be useful: Tales of a Transplanted Gardener

I don't trellis my bush beans either. Pole I do, using 1/2 in conduit from HD and garden twine (~ 2.39 for 10 ft, with clamps two trellises are around $10-11).

Dan

Doh!!

I planted 3 squares in the back row thinking they would need trellising. The seeds have already sprouted a few inches.

Should I transplant them so I make use of the back row for something else?

Why not just let them grow until you harvest the beans. Bush beans are finished after about two weeks of picking, then you could replace them with pole beans and have beans to pick for the rest of the season.

Here is a link that might be useful: Annie's Kitchen Garden