16 for sure, I did 25 in a similar sized bed and things are really cramped now. It also leaves less room for pollinators to get to each flower.
The Hot Pepper
Shorerider
alkhall
I would say it depends on the plants.
Just as an example; Jalapenos need less room than Bhut Jolokia, in my experience. Therefore, I would look at how big each plant will be when mature to plan the layout.
Just as an example; Jalapenos need less room than Bhut Jolokia, in my experience. Therefore, I would look at how big each plant will be when mature to plan the layout.