Here are mine:

{{gwi:2746}}

I have a tangle of cotton string pieces attached to a wooden trellis (with bamboo pole extensions on either side) that sits up against my balcony rail. The rail itself has decorative aluminum fencing that the peas ultimately attach to once they sortof attach to the strings, and they grow and bloom on the outside of the rail/fence. LOL

They do sell plastic mesh for climbers that you can try, although I've noticed with most climbing vines, they prefer to attach to other plants and/or themselves rather than whatever you put in there for them. In that case, you have to manually guide them each day (sometimes twice a day).

i saw the most beautiful photo of sweet peas on a bamboo trellis, and i noticed this method in use at the BBG, as well -- the trellis was made of four bamboo poles making a square, each point being at the edge of the pot, so that it encompasses all ofthe plant, and then there is twine wrapped around the poles, making a little sweet pea cage. they grow real well in there! and i think it's so minimalist and zen :)
heidi

I have old clotheslines on my porch and I tied bamboo poles to them. The peas love them so far (and you can easily chart their progress as the vines climb up the segments)