Hope you don't mind if I start at the bottom and work up? :)

Growing kidney beans worth it? No, not IMO. Takes too much space for any worthwhile production. Plus they need to dry on the vine so all that space is locked up well into fall.

Canning info? That is the Harvest Forum here for all the canning info you need. How-tos are readily available there.

Seeds or plants? Seeds. They do much better than trying to transplant.

Bush beans don't usually need any support. They are bushes and support themselves. But I guess you could use tomato cages if you needed to for some reason. I wouldn't.

Pole beans don't require heavy duty support unless wind is a real problem. If so you can use clothesline or even wire but the string has the advantage of being disposable at season end. If you are concerned just double the string. But many other more effective types of support are available too.

Check out the Beans and Peas forum here for more ideas and even some support pics.

Hope this helps.

Dave

Beans and pea's have its own forum? Ok Thanks!