"peterlsutton" wrote in message
news
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.
Now you have this info you can do a Google search and get the answers to
most of your questions.
i.e. http://www.hydrosource.com/clpbbs03.htm