I really want to try training single stem tomato plants this year. We have three 12x4 beds. 2 run East to West and the other runs north to south. I'm trying to figure out placement- A 12 foot trellis across the north side of the north bed with downward supports every 4 feet? That + trellis's along the East ends I get partial AM shade so East side would optimize afternoon sun. But, I only have two 4 foot sections on the East side & was hoping for five 4 foot sections.

How to stabilize?
We bought 2x2 cedar for the trellis frame and plan on training the plants using the string method so we can easily access the bed and not have to worry about sticking our arms through holes in the trellis. I was hoping to put them a foot into the bed so I can grow up both sides. The hubby is worried if we place the trellises a foot into the bed and run them east to west there will not be enough support and the whole thing will fall over- Any suggestions for stabilizing the middle? Can we drill out the center of the wood, pound in rebar and place the wood over? (Like a wood version of Mel's trellis?)

Please and thank you everyone!