[Lottie Mary]

Finally after what seems like months of waiting I have one orange pepper on my sweet pepper plants.  His neighbour has also followed the trend and is showing signs of orange.  The remainder, however, are still as green as can be! 

This may sound like a stupid question - but do the ripe peppers emit any kind of chemical that will cause their neighbours to turn red too - or is it just a natural progression for each pepper that they eventually turn red?