Hard freezes may come early in the Front Range, killing all but the hardiest plants in the vegetable garden. Although peas, cabbage, kale, parsnips and a few others may survive, planning to dispose of killed plants is a good idea. The carryover of many vegetable diseases and insects can be avoided by doing a thorough fall cleanup.
Early blight fungus overwinters on diseased plants and some weeds. Remove diseased tomatoes plant debris and clear horse nettle and nightshade weeds from the garden. If the disease was severe, consider moving tomatoes to a new location next year if this option is available.
Viruses that affect tomatoes such as TSWV and INSV (tomato spotted wilt and impatiens necrotic spot viruses) cause yellow rings or spots on fruit. If you see these symptoms, remove plant debris because viruses survive in plants, not soil. Note that lettuce, pepper and weeds such as bindweed and nightshade will harbor viruses.
Thrips insects that spread viruses from plant to plant overwinter as pupae in soil crevices or on plant debris. Flea beetles that chew shot holes in leaves spend the winter as adults hiding under leaves, dirt clods and other protected sites.
Fall plant cleanup and fall tillage tend to disrupt all of these pests.