Dig and Store Dahlias
After frost kills the tops of your dahlias, cut them down to ground level and dig the tubers. Store them in a cool place. I place mine in cardboard boxes filled with peat moss and store them in the garage.
Be sure to have some type of protection such as blankets or bubble wrap on hand to protect planters in case of a drop in temperatures. Drain fountains if you haven't already. It's better to be safe than sorry.
Continue to Mow Your Lawn
Mow your lawn regularly until it stops growing. A winterizer type fertilizer will help it maintain good health throughout the winter months. When you have finished your last mowing of the year, make sure that your mower is properly stored. Don't forget to run it until it is out of fuel. Old gas can turn to varnish, and severely damage the engine.
Turn the Soil
Turn the soil in your vegetable garden when you've finished harvesting. Turning the soil will expose many insect pests and their eggs to winter cold, reducing their numbers in next year's garden. You might also consider planting a "green manure" crop, such as winter rye, to help improve the structure of your soil.
Prune Back Mums
After chrysanthemums have finished blooming, cut the stems down close to the ground. Be sure to remove all dropped and dried leaves and old branches from the garden to discourage insects and disease pathogens from hanging around during the winter months.