HOW DO PLANTS SURVIVE ON CONCRETE WALLS?

I have always wondered about this; how do plants grow on walls? Especially old walls. I remember when I traveled to my hometown in Delta State last year. I saw alot of building whose walls had plants growing on them. I know I shouldn't be talking about my hometown like that. But hey this is just me being real as I think out loud!. Delta State has a few cities that are developed. Same as a few underdeveloped places like -- Ugheli, Kwale, Ogwashi, etc. Although people over there are really nice folks.

Anyhoo! Back to the topic; plants that grow on walls, how do they survive?

Who waters them? How did they get to germinate in the first place? Pardon me if some of these questions appear to you like I am uninformed. They are just things that I haven't gotten 'good' answers to. For sure I know about pollination, agents and all that jazz. But my wonder still is; how do these plants survive on wall cracks and holes? How do they keep moisture?

It's not like there are sands on these walls -- at least it doesn't appear that way.
I still wonder how plants get their roots and are able to survive on 'wall concretes'!.

Haven't you thought about it? Well it has been something that has remained a mystery to me.

A look at an example;

      DO YOU SEE ORGANIC SOIL?

     I doubts any plant 
    can grow from there!

ANOTHER EXAMPLE

This is just a ramble book.

If you have a few explanation to my mystery, please I'd love to hear from you. But if you are like me that doesn't see any tangible reason as to the explanation of this mystery, then join me in the comment section let's 'wail' together. Hahahaha

THANKS FOR READING

Find my previous ramblings here

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@dkLeF