Have you ever noticed how many "greens" your house and garden produce during the spring and summer months? And with all of those greens being added to the compost, you'll have a wet, smelly mess in no time if you don't have enough "browns" to balance them out.
But if you plan ahead a little, you can use fall's bounty of leaves to augment all of that nitrogen-rich material in your spring and summer compost piles. Simply fill a few plastic bags (or paper lawn and garden bags) with leaves, and store them in a sheltered, dry spot for the winter. If you use a plastic bag, poke some holes along the sides so the leaves dry well and don't get moldy. Then, when you need some carbon-rich matter to add to your compost piles, you've got a plentiful, free source ready and waiting for you.