I have just bought some water absorbant crystals to mix with compost in
pots - but would like to play with them. 1) What are they chemically
speaking.


Polyacrylamide--which forms a gel with water.

Many thanks Rupert and others for all your help. The chemical name is very
useful and I will have a look on Google - but its too late tonight. The
more feedback you get the more questions come to mind. I am sure it is
worth experimenting with.

Peter