Yes, it is difficult to get enough browns. I found that horse bedding pellets are nice addition since they are just pine shavings. The pellets really soak up a lot of moisture too. It is a rather affordable option if free browns are not available. I am luck in that I have a lot of oak trees in my back yard, so I get a ton of leaves. Having just started my first worm bucket, I am excited to see the worms multiply. Do you sift your castings to separate out the pure good stuff?