[lefrog]

I can t remember where I noticed this thing , but apparentely potato leaf can be used as a pesticide , Alas, I didn t bookmark the site where I saw this thing.
have you ever heard of something similar, or was I hallucinating?

[amberleaf]

I am told that rhubarb leaves in water make a mix that sprayed on to plants stops pest.

Comfrey for manure

Nettles make a tea that act as a plant tonic/food.

Potatoes I would be unsure of using because of the possible risk of passing on diseases like blight.

I dare say that any rotting vegetable matter and water will hold some form of  nutrient.

[woodburner]

Sounds possible, the leaves are full of toxins (alkaloids I think) which is why nothing troubles them at least from the animal kingdom. I'm not sure I'd want them on my tomatoes or runner beans though, no matter how organic the source is!