Posted: 19/07/2015 at 16:59
People put forward many reasons why this happens and I'm sure most people have had it happen at some stage of their growing lives. Some say to cut off the tendrils and you'll get bigger flowers, others say it's determined by the variety you grow, still others say that as sweetpea are hungry feeders, they need liquid feed and perhaps slow acting feed put into their growing medium.
I've found that yes it does happen toward the end of the growing season with them but it definately depends on the variety. Macutania (sp) I grow every year and they get shorter stems about the end of July from an autumn sowing while others like April In Paris are still going strong. Both get fed by me with tomato food for those in containers. Those growing in the ground have some BFB added to the soil before planting.