Southern California Coastal & Inland Valleys
Transplant and Sow Last Veggies
Sow or transplant fava beans, beets, broccoli, Brussels sprouts, cabbage, chard, cilantro, garlic, kale, kohlrabi, leeks, lettuce (especially romaine types and small-heading bibb and buttercrunch types), mustards, green and bulb onions, parsley (the flat-leaf type is hardier than the curly one), peas, radishes, shallots, and spinach (especially the curly-leaved savoy types). While these plants won't grow much till early spring, they'll have well-established root systems ready for the great growth spurt with the first warmth.
Sow Cover Crops
Sow winter cover crops, including fava beans, clover, peas, annual rye, and vetch to be turned under in the spring as green manure. When winter's gloom has settled in, it's nice to see something green besides weeds growing, especially when it'll also fertilize the garden in the spring. You don't need a large garden to grow a cover crop, just consider it a lawn that doesn't need mowing.
Start New Strawberry Beds
Transplant strawberries now so they'll develop sturdy root systems over the winter, ready to burst into lush foliage and heavy fruit set in the spring. Dig in lots of manure and compost first to feed roots over the winter and through the summer.
Plant Onion Seeds or Transplants
You'll get larger onion bulbs that won't bolt in early spring if you sow seeds or transplant seedlings now. Store-bought onion sets (little baby bulblets about half an inch wide) are often left on display indoors where temperatures are too warm for too long, and they frequently bolt during the first spring warmth. If you do purchase onion sets, plant the ones that are smaller than a dime for next year's bulbs, and plant the larger ones to use for green onions through the winter, since these will most likely bolt and set seed instead of bulbing in spring.
Put Roses to Sleep
Discontinue watering and feeding roses, and mulch plants with manure and compost. Prune them lightly to remove the long, bloomed-out canes, but save hard pruning until January, when plants are fully dormant. Severe pruning now could encourage new growth, which will freeze with the first frosts, wasting all that plant energy.