As I've started writing it became apparent I needed to work on my terminology. Perhaps this is not the sexiest topic, but it is important to correctly name the different components of an experiment. That way if someone wants to replicate what you did they will know how. Or, if they are reading the paper (you will someday publish) they will have a clue what you did without the aide of a colorful picture.
Greenhouse: The setting of all this experimentation.
Block: Contains one of each treatment. I have two blocks of six treatments.
Treatment: You remember all the treatments right? They are the independent variable.
Sub-plot: With in each treatment there are six sub-plots for each species. We stuck the three species in one tray because it was convient.
Replicate: Each individual seed.
Just how many seeds is all this? If you could make bets with the bill Salmon P. Chase is on you would be in the right ballpark.