Healthy or not , purple striped stems see pics

The plant looks healthy I think, the stem is striped purple see photos. Please tell me what you think. They look happy any thoughts.

Thanks advance

They look happy to me. It's probably just the cooler nights of fall bringing out a bit of purple coloring. I see nothing to be concerned with.

The plants look great, as stinky said it should be the cold nights. Don't worry be happy!