if you are goin to make your own compost (great idea, i wana get a worm composer for my apartment) and you want a nitrogen source. a good one is coffee grounds. Go to the local coffee place at the end of a busy day and ask for the coffee grinds (hopefully organic/free trade, they you can say your buds are free trade)

keep in mind that there is a lot of nitrogen in coffee so you might want to read about how much to use in your soil mix.