I know every pepper grower has asked this question. Well, I was reading a guide with some "tips on growing peppers" and came across the following....
"How to Grow Hotter Peppers
Hot temperatures and bright sunlight are how to grow chili peppers that sizzle.
In general, the longer a hot pepper remains on the plant, the more capsaicin it will manufacture.
To a point.
You can't turn a jalapeno into a habanaro just by leaving it on the bush for a few more days.
Each of the types of hot peppers falls into a range on the Scoville Heat Scale. All you can do is try to push the variety you are growing to the outer limits of its range. It simply isn't possible to push a pepper plant beyond this genetic limit.
Hot peppers growing in cool climates with short summers will tend to be milder than the same pepper growing in Arizona or Southern California where the summers are as fiery as you want your chilis to be.
For similar reasons, growing chili peppers in a shady location will result in a milder harvest."
http://www.botanical-journeys-plant-guides.com/growing-peppers.html
^^^^Here is the article. Take it as you will. I just thought I would pass on the info.
"How to Grow Hotter Peppers
Hot temperatures and bright sunlight are how to grow chili peppers that sizzle.
In general, the longer a hot pepper remains on the plant, the more capsaicin it will manufacture.
To a point.
You can't turn a jalapeno into a habanaro just by leaving it on the bush for a few more days.
Each of the types of hot peppers falls into a range on the Scoville Heat Scale. All you can do is try to push the variety you are growing to the outer limits of its range. It simply isn't possible to push a pepper plant beyond this genetic limit.
Hot peppers growing in cool climates with short summers will tend to be milder than the same pepper growing in Arizona or Southern California where the summers are as fiery as you want your chilis to be.
For similar reasons, growing chili peppers in a shady location will result in a milder harvest."
http://www.botanical-journeys-plant-guides.com/growing-peppers.html
^^^^Here is the article. Take it as you will. I just thought I would pass on the info.