I have my plants in a container. They are now about 5 ft tall and the bottoms of the plants are starting to turn brown. Why, and can this be fixed? Thanks.
Most of the time, brown leaves at the bottom of any plant simply means that the foliage on the upper part of the plant is blocking out some of the sun, and it's nothing to worry about as long as your plants are in full sun. Sometimes it can be indicative of overwatering, which is something peas are highly susceptible to. This article may help you: https://www.gardeningknowhow.com/edible/vegetables/peas/grow-peas-in-containers.htm
It doesn't sound like you have any disease or pest issue, but check this article so that you know what else to look for: https://www.gardeningknowhow.com/edible/vegetables/vgen/brown-leaves-on-vegetables.htm