I would appreciate a link to a good plant diagnostic site... based on
symptoms, like if a plant's leaves have brown spots, are curling, it's due
to xxx and you would need to yyy...



It's not quite that simple, because different problems can cause similar
symptoms. However, check out this page:

http://www.csd.net/~cgadd/aqua/art_plant_nutrient.htm


Leigh

http://www.fortunecity.com/lavender/halloween/881/