North American Fruit Explorers mailing list at ibiblio

["Rodney Eveland" <reveland@collinscom.net>]

Potassium hydroxide (the main active ingredient in wood ash) is used
to raise the ph of hydroponic solutions as plants need potassium.
Sodium hydroxide creates sodium compounds which are generally
considered bad for plants. Both hydroxides will rapidly convert your
skin and flesh into new chemical compounds if you put your hands into
very concentrated solutions of them. It is a fertlizer if it is
neutralized down to a low ph by the soil it is added to.

http://www.sgs-hydroponic.com/keywords.php?cat=675&keyword=potassium%20hydroxide%20ph
as used to raise ph

http://www.growroomsuk.com/pHup.html      as used to raise ph

http://www.engineeringtoolbox.com/13_402.html      ph of common bases

http://www.nutri-tech.com.au/products/biomanagement/potassium-hydroxide.htm   
     as used in fertilizers