Making a small fish pond surrounded by my fund patio, and for the liner is it possible to use a substantial weigh pool liner? I think this should work, and this pool liner is heavy and...

I think this should work, and this pool liner is heavy and contained by good shape.
Making a herb garden.?
Answers:    Pool liners are made from PVC or poly-vinyl-chloride. This is agreed to leach into the water. It is considered safe plenty for skin contact but not safe enough for drinking. This is why you can see drain pipes made from plastic but supply pipes are copper, steel, or brass. Once again if you rob a look at some garden hoses some carry a label alert you not to drink from them.

Proper fish pond liners are made from rubber. This substance is similar to inner tubes that are put inside bicycle tires. This is a safe substance to use for a liner. If however you don't plan on putting anything living surrounded by your "fish pond" then you can use your pool liner.
Can you grow potatoes from sprouting potataoes and...
It should work, but it will look weird. Pool liner is usually oil lamp colored but garden pond liner is black -- for a reason. Garden ponds get algae and are dirty, unlike a swimming pool.
Does anyone hold a coast style garden?
Black is what color you involve. Find some old carpet and flash the pond with the carpet first earlier putting down the liner.It will protect the liner and give it a good substructure.(Soft side up.)