Plant Cool-Season Vegetables
Sow seeds for root crops (beet, carrot, kohlrabi, leek, onion, parsnip, radish, rutabaga, and turnip), all types of greens (chard, collard, endive, leaf lettuce, mustard, and spinach), and peas. Sow or transplant cole crops (bok choy, broccoli, Brussels sprouts, cabbage, cauliflower, Chinese cabbage, and kale).
Plant a Cover Crop
If your garden remains fallow for a season, plant a cover crop. It will inhibit weeds, which can gain a tenacious toehold in a short time. Try a legume, such as clover or vetch. Legumes generate their own nitrogen, which helps build nutrient-rich soil.
Add Landscape Plants
Fall transplanting allows trees, shrubs, groundcovers, vines, ornamental grasses, perennials, cacti, and succulents at least seven months to establish roots before summer heat returns. Dig a transplant hole that is only as deep as the root ball. This helps prevent the plant from sinking too deep after soil settles. Also, dig the hole three to five times as wide as the root ball. This loosened area promotes speedy horizontal root movement through the surrounding soil.
October is the perfect month to sow native wildflowers. Read package mixes to make sure they contain appropriate native varieties adapted to local soil, temperature, and rainfall. In the low desert, good performers include arroyo lupine (Lupinus succulentus), desert bluebell (Phacelia campanularia), desert marigold, fleabane, Mexican gold poppy, owl's clover, penstemon (P.eatonii and P. parryi), and tidy tips.
Stop feeding citrus, hibiscus, lantana, natal plum, and other frost-tender, non-native tropical plants. Feeding now encourages new shoot growth, which is susceptible to frost damage.