Serrano chillies

When to Pick Serrano Peppers
Unripe serrano peppers start out green in color and will typically grow to 3 or 4 inches in length on the plant. As with any chili pepper, you can pick and eat them at anytime in the growing process, though the flavors will change as they ripen. Eventually the serrano pods stop growing and will then change color, from green to red, brown, orange or yellow. After that they will fall off of the plant and can even rot on the plant, so it is best to pick your serrano peppers while they are still green or as they begin to change color.