1. Plan you final harvests. Some crops can be damaged by gentle frosts, while others are more tolerant of the cold. Harvest non-hardy crops before the temperatures fall to avoid losses. Mark and winterize hardy plants that you plan to continue harvesting from into the late fall and winter. Kale, leeks, brussels sprouts, and other plants can be productive into much colder weather than most plants, so don't give up on their valuable harvests, even when frost has started in your area.
2. Clean out garden debris including old vines, weeds, spoiled vegetables, or other plant material that accumulated over the season. Plant material from the previous growing season should be brought to a composting area where temperatures get high enough during the composting process to eradicate any microbes that might be present. Once organic matter is composted fully it can be used to recharge your soils for the next growing season. If you know that some plant material from your garden was infected with a disease or pest that is difficult to eradicate, it may be best to remove the debris completely to avoid spreading it to other crops in the future.
3. Add compost or other soil amendments to the top of the garden bed. Adding some amendments in the fall will allow nutrients to be incorporated. If you are planting a cover crop for overwintering, read the planting recommendations for your area and soil conditions before deciding what to plant.
4. Plant over-wintering crops in areas that won't be disturbed in the spring. Some plants, such as garlic, need cold temperatures in order to be productive, but still require growing time in the spring and summer months.
5. Clear and prepare your root cellar or storage area. Storing vegetables over the winter is a valuable way to extend your garden harvest for weeks or months past the growing season. Different vegetables and fruits have different storage requirements, so be sure to research the best storage methods for your own crops. Before adding new produce to any storage, be sure to clean out storage containers and racks from previous years, as well as remove any items that have spoiled. Continue to monitor your stored crops throughout their time in storage, and remove any items that are not keeping well.
6. Make a notated garden map. Take a few minutes to make a map of your garden, and add notes about the productivity of your plantings this year. Make notes on things you'd like to change about plant varieties, growing conditions, or placement that you want to incorporate into your garden next year.
By taking the time to put your garden "to bed" for the year you will help yourself to a quicker start to planting in the spring, as soon as the temperatures rise again!