Beautiful, dry fall days are perfect for cleaning up the gardens before winter and leads to much less work the following spring. My mantra is “If it is brown, cut it down”. Old, dead and dry plant material can harbor insects and diseases that will use this material to spend the winter protected and in place, just waiting for the warm winds of spring to awake to another year of attacking your garden. If you had a problem with insects or disease, remove that plant material to the garbage rather than the compost pile. The compost pile will have to reach 120 degrees F to kill insects and higher to kill most disease pathogens. Most of use do not monitor, never mind manage, a pile correctly to reach those temperatures. So it is better to just remove the infected plants to the household garbage. One other option is to bury them at least one foot deep in the ground
Timing of fall clean up depends on the the first frost mostly. No need to remove still producing plants such as dahlias or kale and possibly some healthy tomatoes. Once the first killing frost happens, there will be many plants to remove. I prefer to gradually remove plants that have petered out and struggling, making the job easier over an extended period rather that doing it all in one muscle-aching long weekend. Have a soil test to determine your pH level and nutrients available. If lime is needed to raise you pH, it will need 6 to 9 months to fully react therefore fall is a great time to add it to the soil.
There are some plants that do not need be to cut back now, but left up for winter interest in the garden, or if they have good seed heads birds and animals can use for food. Sedum ‘Autumn Joy’ and some others have strong stems that stand up during winter and also have great seed heads that draw the goldfinches. Echinacea is another seed producer with stems that will stand up to snow cover.
Now is the time to make notes about certain areas and plants that will need to be moved or added to in the spring. Bulbs can be planted and marked with colored golf tees to remind you just where you planted them! I have tendency to forget the exact spot of bulbs plantings whose foliage and flowers are long gone by the end of summer. Poppy seed, annual and perennial, can be spread to in fall. They will germinate in early spring after meeting their cold requirement. I have an annual variety the self seeds that I find popping up in different areas. Once they have two sets of real leaves, I dig and move them around to where I want them. While cleaning up, watch for any weeds that have seed heads. These should go in the trash, not the compost to further reduce weed seeds in the soil.
In the vegetable garden, remove all tomato and potato plant material to prevent volunteer plants next year. If you had late blight fungus this year, it can overwinter in plant tissue, such as a missed potato in the bed, only to grow an infect potato plant next year that has the possibility of infecting your new potato plants. Rotate crops by planting potatoes in a different bed the next year. Any potato plants appearing in the old bed should be pulled and destroyed, not placed in the compost pile.
Finally, a layer of leaves can be placed on top of the garden soil as a mulch. In our yard, we mow the lawn in a circle or square pattern with the discharge pointing inward to the middle of the square. As the lawn and leaves are mowed, each pass makes the square smaller and deposits the chopped up leaves into a pile. We then rake them up and lay them down on the garden beds. The small pieces will be almost completely decomposed by planting time next spring and I am adding needed organic matter to the soil.