Agave and Hesperaloes

I have a few questions concerning plants and seeds.  First:  I have a 
newly acquired A. attenuata that I've planted for the time being in a 
pot as it's fairly small.  It seems to be growing fine, only it's not 
near as green as portrayed in photos I've seen, and I fertilized it 
last week with no change as of today, and it gets full sun for at 
least 2/3 of the day.  What are the optimum conditions for growing 
one of these successfully?  It's so different from my other agaves.

Secondly:  I have both yellow and red Hesperaloe parviflora seeds 
that I'd like to sow.  Can someone give me any information on how to 
successfully germinate them?

TIA

QB