Andi - its readily available here at most local garden centers/hardware stores and what not- as well as feed stores. most gardeners around here stay away from the pellets that are used for feed purposes however, due to them having other ingredients that are not necessarily good for plants. if you get the pellets be sure to only use the ones that specifically say, "100% alfalfa". the meal usually costs about $8 - $10 for a 5-6 pound box. it can be ordered in bulk online as well. which is a much better deal.
http://www.tools2parts.com/Dow...
we use it on ALL of our flowering plants. especially dahlias! 2 cups per bulb. we used it on our dahlias last year for the first time, that's when we first discovered it. there were blooms GALORE! it was unreal.