Toward the end of September I planted peas. The plants have done very well...
Peas planted in the fall usually perform poorly. It takes 50-70 days to maturity and are planted in mid July to early August. You did not have a long enough growing season. They do not germinate readily in warm soils and a killing frost can arrive before the pods mature. Peas like a cool temperature but the blossoms can be affected by a frost. They grow best in the spring favored by
(65 degrees-70 degrees F) temperatures while flowering is accelerated by long days with cool air temperature.
as well as our profile on peas http://extension.umd.edu/learn/vegetable-profiles-green-peas