At higher elevations, frost has already put down many plantings for their long winter's nap. Lower elevations, like Phoenix, will see frost by mid-month.
In all locations, as freezing temperatures come and go, you can prolong the growing season by protecting plants.
Move outdoor potted tropicals to a protected spot on a porch or covered patio if frost threatens. For tropical succulents, like desert rose (Adenium obesum), keep plants under cover through winter to protect from seasonal rains.
Test Garden Tip: Frost helps some vegetables -- like Brussels sprouts, kale, and carrots -- develop better flavor. Many leafy greens, including spinach and lettuce, withstand hard frost (below 28 degrees F).
Continue to plant this month, from herbs, to wildflowers, to shrubs.
From seed -- borage, cilantro, dill, perennial fennel, biennial parsley. Growing Tip: Plant herbs where they'll receive as much winter sun as possible.
From seed -- nasturtium, sweet pea. From transplants -- sweet alyssum, pansy, viola, dianthus, petunia, snapdragon, flowering stock. Growing Tip: Remove spent blooms to encourage future flower bud formation.
From seed -- (annuals): desert bluebells, Mexican poppies, owl's-clover; (perennials): blackfoot daisy, native verbena, penstemons. Growing Tip: Keep soil moist until seeds germinate. If rains don't come, water every two weeks.
Agaves, Cleveland sage, lavender, Senna purpusii, banana yucca. Growing Tip: Remember to keep roots consistently moist until plants are established.
Indoors -- paper-white narcissus, amaryllis. Growing Tip: Plant a few extra pots of these easy-growing bulbs to give as holiday gifts.
Test Garden Tip: Citrus crops, including orange, grapefruit, lemon, lime, and kumquat start ripening this month. Harvest only what you'll consume immediately; allow remaining fruit to continue ripening. The longer fruit stays on a tree, the sweeter it becomes.
Reduce irrigation, especially on cacti and succulents. Colder air lowers plants' moisture requirements, and seasonal rains should provide sufficient water during winter dormancy.
Add composted manure to vegetable gardens and planting beds now. This is also a good time to add other nutrient-rich top dressings to soil. Winter rains will help wash nutrients into soil.
Keep an eye out for rabbit damage to agaves, cacti, and yuccas if winter rains arrive to the region slowly. Rabbits tend to feed on wildflower and weed growth that's kicked into gear by the rains. When rains delay, these rodents expand their dietary repertoire to include nontraditional plants.
Some plants blaze with eye-catching fall color this month: Arizona and desert rose mallow, sumacs, native plumbago, and Mexican buckeye.
Clip garden mums and peonies to 6 inches after frost nips foliage. Leave stems in place until spring as a marker indicating where dormant perennials are located. Cut stems to the ground in spring.
Test Garden Tip: Tuberous bloomers that stage a summer show disappear this month. Among those departing are four o'clocks, butterfly weed, Datura wrightii, and globeberry. Mark plant locations using colorful golf tees, making sure not to disturb or irrigate plants all winter.
Test Garden Tip: If you have warm-season turf that's dormant, service your mower while you're not using it. Sharpen the blade, and check and/or replace the air filter. Determine if it's time to change the oil according to schedules in your owner's manual.
As you stow tools for the garden's dormant season, take time to prep them for another year of use.
Test Garden Tip: Remove hard water mineral deposits on hose connections, spray nozzles, and watering wands by soaking affected pieces in vinegar. An overnight soak should loosen and remove stains. Rinse with warm water and dry before storing or using.