Answer: Chili peppers will eventually turn red if left on the bush long enough. You can pick the fruit anytime after it reaches full size (which varies between varieties). If you pick them soon after they reach full size but before they start to turn red, you will probably get a larger quantity of harvest. If you allow them to turn red, which they will do in time, you will get (in my opinion!) a better flavored pepper, and certainly one with many times higher vitamin A content. The tradeoff is that the bush will tend to not produce as much.
Enjoy those peppers!
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