Sow Grass Seed
Now is a good time to either seed a new lawn or patch up bare areas in existing lawns. The new grass will grow until late in the fall when the ground freezes, but frost will take out any annual weeds that have sprouted, allowing the grass to fill in without competition from them.
Practice Good Garden Sanitation
Lots of insects and disease problems get carried over the winter on plant debris. So if some of your plants had problems this past season, clean up and dispose of all plant materials that show symptoms at the end of the season. Unless your compost pile is a hot one, it's a good idea not to add any obviously infested or infected materials to it. Instead, put problem material in the trash, bury it, or burn it.
Give Your Amaryllis Bulb a Rest
If your summered your amaryllis plant outdoors, be sure to bring it inside before the first fall frost. Most likely its leaves are beginning to yellow. If your plant still has green leaves, stop watering to allow leaves to wither. Cut off the dead leaves, then move the dormant bulb to a cool (55 degree F) spot for an 8-10 week rest. You can store the bulb in its pot turned on its side, or remove the bulb from it pot and store it on its side. Once the rest period is up, repot the bulb, move it to a warm, bright spot, and begin watering again.
Plant Trees and Shrubs
Fall-planted conifers such as pine and spruce do best when they go in the ground from mid-August through September, while the soil is warm. Many other kinds of container or balled-and-burlapped trees and shrubs can be planted successfully later into the fall, including maples, ashes, lindens, elms, and most deciduous shrubs. Getting plants in the ground by mid to late October will allow for the most root development and best establishment before winter arrives.
Fertilize Trees and Shrubs
According to UMass Extension, the common assumption that fertilizing woody plants in the fall stimulates new growth that will be likely to suffer winter injury is not true. Recent research has shown that the nutrients that trees and shrubs need to fuel new growth in spring are actually taken up the previous year and stored over the winter. This led to the conclusion that late summer and early fall are the best time to fertilize woody plants, and that doing so will increase, not decrease, their winter hardiness. Most woody plants are not heavy feeders, so apply fertilizer only if plant vigor or a soil test indicate a need.