I enjoy getting your "Fiery-Foods and Barbecue Magazine." I’m growing 30+ varieties of peppers this year in my container garden. Same spot for 6 years now. Problem this year is that my peppers have very little heat. Using the same seeds as have used years before. Extremely hot and dry this summer. I live near Kansas City, MO. Orange habs, Red Savina, Biker Billy & many other varieties are very mild compared to previous years. My fertilizing, soil mix and watering habits are pretty much the same year after year. Is it the increasing lack of direct sunlight that could be causing this problem? Depending on the time of year my plants get only 6-8 hours of direct sun at the most. I cut down more trees every year but am still losing some sun each year as the remaining trees get taller. Does the intensity and duration of direct sun during the growing season have an affect on the amount of capsaicin produced?
The environment plays an important role in capsaicin production. Generally, chiles are hotter if they are stressed. Lack of sunlight could play a role, but I don’t think anyone has done a study on this. Try witholding water until the plants just start to wilt. Do this a while and see if the pods are hotter. Generally speaking, the more mature a pod, the more capsaicin it has, so pick only mature pods if you can.
Environmental effects on Capsaicin Production