With cooler temperatures come beautiful autumn leaves and more yard work. Instead of stuffing the leaves you rake into plastic bags destined for the landfill, see if your community has a drop-off site to have them composted. If not, consider this less pretty, but much greener idea: Run your lawnmower over the leaves. Then they can be left on the grass to decompose over the winter season. They'll be beneficial nutrients for the lawn, leading to a greener, healthier yard next year.