1. Make notes about this year’s successes and failures.
2. Turn extra tomatoes from your garden into tomato paste.
3. Take and root cuttings from container annuals that you want to keep for next year.
4. Divide spring-blooming perennials.
5. Build a compost bin.
Stock up on notebooks and pens at back to school sales so you can make notes about what worked in your garden this year and what didn’t. For example, perhaps you allowed wild evening primroses to remain in your vegetable garden just because you liked their flowers. A fortuitous choice, since those evening primroses proved to be a natural Japanese beetle magnet and lured the bugs away from your other plants. Write that down now, or next year you may be scratching your head over which weed it was that kept those beetles occupied.
You may also want to take notes about how to preserve your extra tomatoes as paste. If you don’t have the time or the inclination to can them, you easily can freeze them instead. Naturally, paste tomatoes generally work best for this, but you can use others . They just will require longer cooking to boil them down.
After washing your tomatoes, pare out their stems and any rotten spots, and cut them into pieces. Drop those pieces into a blender and run it on high for long enough to liquefy the tomatoes. Pour them through a strainer into a saucepan, as the mesh of the strainer will catch and remove the seeds and skins.
After bringing the strained paste to a boil, simmer it on low, uncovered, stirring it occasionally, until it boils down to the consistency that you prefer. You then can simply pour however much you generally use in recipes into individual freezer bags. Or, if you prefer, you can freeze the paste in ice cube trays first, to convert it into convenient size blocks, before inserting those blocks into freezer bags.
Speaking of preserving, if you have especially choice container annuals that you would like to keep over the winter, it’s a good idea to take cuttings from them now. The types most likely to survive on windowsills indoors are those which can flourish in low light—such as coleus, wax begonias, and fuchsias—and those which can tolerate dry conditions—such as pelargoniums.
Most of those plants will root easily in water. For instructions on that, see Rooting Cuttings in Water on Your Windowsill. If you prefer the traditional method for cuttings, see How to Root a Tree with Root Hormone. You need only change the amount of rooting hormone—based on whether your cuttings are softwood, semi-hardwood, or hardwood—to make the article applicable to plants instead of trees.
In reference to other plants, autumn is a good time to divide spring-blooming perennials, since they flourish during cooler weather. That would include primroses, creeping phlox, brunnera, etc., as well as the more problematic peonies. Because they don’t like having their roots disturbed, peonies shouldn’t be moved unless it is absolutely necessary, since they often will stop blooming for a year or two to allow themselves time to recoup. But, if you must relocate them, autumn is the time to do it.
Early autumn also is a good time to build yourself a compost bin, for all those leaves which will be plummeting from the trees shortly. Although such bins can be expensive to purchase and ship, you may be able to construct your own from materials you already have on hand.
Keep in mind that the bin’s floor should be the ground, preferably level ground, and its walls should be constructed of permeable materials (which will admit air). Those might include wooden pallets, woven wire fencing or screening, lattice panels, straw bales, landscape timbers, cement blocks, etc. With a little imagination, you may be able to use recycled junk as an enclosure in which to recycle your leaves and leavings!