I've been working that out, and have come up with a few suggestions you may not have considered as sources for "brown" material for your garden:
1. Dried leaves and grass. Yes, it's true we won't have a ton of dead leaves until fall ... but the recent Hailpocalypse we had in Ohio brought down a lot of leaves and small branches in our yard. I left everything out to dry for a few days, then gathered a giant garbage can load of it into a pile next to my compost bin. I've been forking in a few scoops of the now-dried leaves every time I add kitchen scraps to the compost, and in only a few weeks I've used most of it up. The same thing works for grass clippings - leave them laying on the lawn for a day or two before you rake them up, then add the dried grass gradually as you add in the kitchen scraps. It won't win you any "lawn of the year" awards, but it does keep the stuff out of the landfill (and prevents it from going all matted and slimy in your pile).
2. Shredded paper. We started a bin for recyclable paper a month or two ago, and while Liza was in school I was taking it over to the fundraiser bins they have in the school parking lot. But I'm not going to drive all the way over there this summer, and the paper load was getting pretty large, so I hauled out the crosscut shredder and got to work. We shredded junk mail, and Liza's old school papers (with her permission), and even some paperboard boxes.
Some of it went into the pile immediately, while a fill grocery bag of the stuff is sitting by the back door, ready to be added to the pile with the kitchen scraps. I figure a good couple of handfuls of paper per load of kitchen scraps ought to help keep things in balance. Just remember that paper is really dry, and needs to be moistened when you add it. You can either spritz the paper down with water from a sprayer before you add it, or just use a hose to add some water to the pile as you mix it in.
3. Vacuum cleaner dust. Yes, I know, it's kind of gross ... and technically it's probably a "green" instead of a "brown," but it helps separate out the slimy green layers, and it's better than throwing it out, right? It will take a while to decompose the hair, but it's supposed to be a really great source of protein for the pile, so I'm all in favor of it.
4. Ashes from the fire pit. Seems like everyone has one of these nowadays, but I don't see many people adding the ashes to their compost piles. They're a great source of "brown" material, they don't smell bad, and they help aerate the pile (because some of them are in bigger pieces and/or have holes in them that trap air).
Just don't add any ashes from charcoal briquettes or those chemically-treated "fire logs" you can buy at the home stores ... I don't think any of us want the petroleum products they use to make those in our nice, healthy piles! And let the ashes cool completely before you add them - we want our pile to be hot, but not aflame!
5. Cardboard. It's strawberry season here in Ohio, which means that I'm bringing home lots of those pressed cardboard berry boxes from the farmers' market. They can't be reused much in the home as they get soggy really quickly, but if you pull them into smallish pieces, they make excellent compost material. You can do the same thing with egg cartons (but they're harder to pull apart) and even low quality cardboard boxes. You can also find compostable paper plates, which work well for parties and can be used in your pile afterward. Most cardboard we send out to be recycled, but if you're desperate for brown compost material, you may want to chop some up and throw it in your pile.
