Compostable?

We went to ModMarket for lunch yesterday. Their cups are compostable, but I don't know exactly how that works. So I took a cup home and put it in our worm bin. We moved the worm bin into the greenhouse. The greenhouse is being used mostly as a storage facility.

The bin in the greenhouse.

Lots of fruits and veggies, and a cup.

Let's see what happens!

I like ModMarket because it is affordable, delicious, and somewhat healthy. They also use FourSquare and Twitter for marketing. I got a free pizza for having 10 FourSquare checkins.
Now there is another fire that is closer to Boulder than the last one. For now it is smaller, but the winds are howling. Is it bad that I worry how it will affect the fish in Boulder Creek more than anything else?