How do sweet peas know which way to grow to grab a fence or post? I have seen them lean over to grab a post.?

And some people will tell you there is no God. I think one of the most amazing wonders in nature is how plants know things. Like, how do they know to grow their leaves and branches out to a point so sharp that it can pierce your skin with only minor pressure. How do they know what causes us pain? It blows the mind.

How do sweet peas know which way to grow to grab a fence or post? I have seen them lean over to grab a post.?
They don't "know". They just do. Like ivy, or clamatis, or any other climbing plant. Some do and some don't. Cucumbers will climb a trellis if one is close enough, if not they just run along the ground till they "touch" something. I bet it has to do with the natural instinct to put as many leaves as possible as high as possible to get as much sun as possible. That sounds possible! :)
Reply:Although they seem to "reach out and grab" something that they can't possibly SEE...it's not sight that gets them there.





If you were to film the plant 24 hours a day, and then speed it up to look at it, you'll find that it moves around quite a bit while growing. If the tendril actually hits somthing, it will impede the movement long enough so that the quick growing tendrils' sprialing affect will catch the object.