You won’t have to clean your whole garden at the same time since plants have varied lifespans, but be sure to pull any plants that are infested with pests or diseases.
By neglecting to remove a diseased plant, you can actually do more harm than good, as many diseases are soil-borne and can quickly infect other plants.
In warm climates, you may be able to grow a full-season fall garden; just be sure that it will grow to maturity before the first expected frost date in your region.
Instead of doing a fall garden, you can grow cover crops to keep your soil protected to reduce weeds, avoid topsoil erosion, and protect beneficial insects.
These crops are like placeholders that act as a regular garden but without any tending. Just loosen the top inch of soil, scatter the seeds, cover them, and let them grow.
After removing all your summer plants, clear out the weeds and add 1 or 2 inches of good-quality compost, then a few inches of mulch as extra of protection.