Hello RainbowGardener,
I have three different size boxes in my garden. I planted Tomatos in 3x8x12. I agree it's very crowded! I read that one could crowd tomatoes in raised beds for higher yield. I did the same last year but about 15 plants per box. But I kept it pruned. We will see what happens this year with the added plants. So far no problems, tho I am concerned the bees aren't getting to the flowers as easily. There are Nasturtiums, Marigolds and Borage in the box that have been over taken by the tomato plants.
Here is a pic from last year.
The difference is I made custom cages this year for the box and put in irrigation that I will attach timers to. I live several miles from my garden plot and can not get to water it daily in the summer. My garden is in a 10 acre community garden. Each gardener gets a undeveloped 60X60 plot and you develop and grow it "your way" within the rules of the garden. I am the only one with raised beds.
I do try to feed my plants compost tea every two weeks. We have been reaching temps in the 80s and 90 since May! I prune less on the west facing side of the tomato boxes to prevent the fruit from getting sun burned.
I hope I didn't overcrowd my boxes this year. It's been in the back of my mind and I need to spend the time to at least prune soon. They are starting to hang out too.