Now the tomato plants, starting with the one on the right hand side of the picture and moving over started to turn yellow. Then the leaves would die and it would spread to the rest of the plant. Now the first plant I planted had lost most of its leaves so I cut it down and did some investigating. I dumped out the soil from the bucket to get a look at the roots. I was expecting root rot or something but the roots look great.
Those tomatoe plants were huge, I think they have just run their course. I am already on my second planting of tomatoes this year. I would just start some more and not worry about you peppers to much, the larger ones look very healthy.
Could be Fusarium Wilt http://ohioline.osu.edu/hyg-fact/3000/3122.html
Fusarium wilt symptoms begin in tomato and potato as slight vein clearing on outer leaflets and drooping of leaf petioles. Later the lower leaves wilt, turn yellow and die and the entire plant may be killed, often before the plant reaches maturity. In many cases a single shoot wilts before the rest of the plant shows symptoms or one side of the plant is affected first . If the main stem is cut, dark, chocolate-brown streaks may be seen running lengthwise through the stem . This discoloration often extends upward for some distance and is especially evident at the point where the petiole joins the stem. Potato tubers may show browning of the vascular ring as well as browning at the stem end and decay where stolons are attached. In pepper, lower leaves do not begin to wilt until roots and the base of the stem have already started to decay. Wilting of the entire plant soon follows. Dark brown, sunken, and eventually girdling cankers may be seen at the base of the pepper plant. In eggplant, wilting progresses from lower to upper leaves, followed by collapse of the plant.
looks like they have been sprayed with weedkiller or something , i have seen Fusarium Wilt i do not think it is that but i could be wrong have fast did it take them to die ????do you have any neighbors or teenagers around that could have give them something bad... just some suggestions