How big do they get before they die? What is the first sign that things are going bad?

Do not fertilize at first.. let the seeds sprout and wait awhile before you fert... It is probably a ph problem and not a fert problem.. and don't over water..

can you post pics.. I'd love to hear about a successful grow in China!! : )

good luck

It may be tough if you can't get a ph tester.. you should be bale to find some sort of Ph tester.. even in China.. : )