Do A Search a the bottom of the page in the Bamboo Forum
Type in( Starting Seeds ), There is alot of information about how to start bamboo seeds .Temps,soil,and stuff like that.
How many seeds you got and What kind ?
I'm no expert , I started 12 Moso seeds off Ebay,have two
that are still alive one year old. Both are in the same pot.
one is about 5 inches tall, the other is about 2 inches tall.
I think I damaged the root system trying to repot into a bigger container. they have been in the greenhouse over winter and they are sickly looking.I have them in Miracle Grow potting soil with moisture control.
Hope This Helps

Here is a link that might be useful: starting seeds link