Mel's book says N-S is better to catch the sun all day and not overshadow the other plants. On the other hand I see you are from Florida, like me, and in Florida a little shade from the western sun is not a bad thing at all. This is my first year really trying a trellis so I am not sure.

If the beds run N-S, where do the trellis' or tallest plants go to prevent shadowing other plants?

If your goal is to not shade out other plants in your garden, then run the trellis along the north side of the garden running East-West.

If no other plants will be shaded, and your goal is to get equal amounts of sun on each tomato plant, run the trellis North-South. If this is the case, as one poster noted, a little shade on the western side of the trellis may help to prevent the hot late afternoon sun to cause any issues.

Hope that helps!
Susan

Due to the topography of our property (and limited available space for a garden)mine run sw/ne and do surprisingly well. If a person were to connect all of my trellises end to end, the entire thing would be about 50 feet long, and average about 6 feet tall. With all of that said, i've defied every last recommendation that Mel's book suggests for trellises out of necessity, and prevailed....just my two cents..

Here is a link that might be useful: Where it all takes place