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Plant garlic and spring bulbs
Per OSU Extension, fall is the best time to plant garlic in Oregon. In the western lowlands (zones 8a–8b), mid-October is the usual target, once the first rains have softened the soil (see the September guide). WSU Extension's garlic publication gives the same fall timing for Washington.
- Plant individual cloves pointed end up in well-drained, compost-amended soil. Raised beds help in heavy clay that stays wet all winter.
- Mulch with straw after planting to limit soil splash and winter weeds.
- Use the largest cloves from certified or local seed garlic, not grocery-store bulbs.
Spring bulbs (daffodils, tulips, crocus, alliums) go in through October and into November. Good drainage matters more than anything else. Bulbs sitting in waterlogged clay over a PNW winter often rot.
A common rule of thumb is to plant bulbs about two to three times as deep as the bulb is tall, pointed end up. Daffodils and alliums are reliable perennials here, and squirrels and deer tend to leave them alone. Tulips often come back weaker each year in wet west-side soils, so many gardeners treat them as annuals or grow them in containers. Hardneck garlic sends up edible scapes in late spring and is often rated better for flavor. Softneck garlic stores longer.
Settle in the winter vegetable garden
Crops for fall and winter harvest should be close to full size by now. WSU Extension in Snohomish County explains that growth all but stops in the short, dark days of late fall and early winter. Your winter garden is mostly what is already in the ground. Kale, collards, leeks, chard, overwintering cauliflower and purple sprouting broccoli are the reliable west-side crops. OSU Extension's growing-winter-vegetables guide covers which crops hold best through winter.
- Sow fava beans and overwintering onions in October in mild west-side gardens. Both are winter-hardy in the western lowlands.
- Have cloches or row cover ready for hard frosts. They also keep rain from beating down tender greens.
- Bring winter squash in before heavy rain and frost. Cure it somewhere warm and dry, then store it cool.
- Pick the remaining green tomatoes before the first frost and ripen them indoors. Late blight spreads quickly once fall rains settle in.
Pull spent summer crops as they finish, and keep blighted tomato and potato foliage out of the home compost pile. Beds that held tomatoes this year are good spots for next year's peas, beans or brassicas.
Check price
OSU's case for fall slug control is to stop egg-laying before winter, and iron phosphate bait around new garlic and fall transplants is the pet-safer way to do it. See how we chose it.
Harvest, storage and tender plants
OSU Extension's October garden calendar is largely about harvest and putting the garden to bed.
- Apples and pears: finish picking late varieties. Pears ripen best off the tree. Pick them mature but still firm, chill them, then ripen at room temperature.
- Potatoes: dig them before the soil turns waterlogged. Let them dry briefly out of the sun, then store them cool and dark. Throw out any with cuts or rot.
- Onions and garlic from summer: check stored bulbs and use any soft ones first.
- Tender perennials: fuchsias, geraniums, tuberous begonias and other tender container plants should come in before the first frost. Check them for aphids, whiteflies and spider mites before they go indoors. A cool, bright, frost-free spot is ideal.
- Seed saving: collect dry seed heads from beans, peas, flowers and open-pollinated vegetables on a dry day, and store the seeds cool and dry.
Slugs: fall is the time to hit them
Per OSU Extension, fall and spring are the prime times to go after slugs. Slugs that are controlled in fall don't lay the eggs that hatch into next spring's population. OSU's slug control guide recommends combining several methods:
- Clear boards, pots, dense groundcover and debris near vegetable beds where slugs shelter during the day.
- Hand-pick or trap them in the evening and after rain.
- Scatter iron phosphate bait lightly around new transplants and garlic beds. Reapply after the bait breaks down in rain, as the September guide describes.
Go out with a flashlight an hour or two after dark on a wet evening. You will see how many slugs you are dealing with and where they come from: usually a nearby edge of ivy, a woodpile or an unmowed strip. Fixing those spots does more over the long run than bait alone. Iron phosphate is the preferred bait where pets and wildlife visit (see the March guide).
Protect soil from winter rain
Bare soil left to the winter rains crusts, compacts and loses nutrients. The September guide set September 30 as the target for sowing cover crops. Per OSU Extension, cover crops protect soil and support pollinators over winter. If your beds didn't get one in time, cover them instead:
- Spread a few inches of shredded leaves or straw over empty vegetable beds. It will be mostly broken down or easy to rake aside by spring.
- Use the leaves from your own trees. Shredded leaves stay put better than whole ones and break down faster.
- Stay off saturated beds. Footprints in wet clay leave compaction that lasts into spring.
Lawns: moss and the last fall chores
The September overseeding and fertilizer window has mostly closed in the west-side lowlands. Mow the lawn at its normal height as long as it is growing, and rake leaves off it before they mat down.
Moss comes back with the rains. Both OSU Extension and WSU Extension describe lawn moss as a symptom, not a cause. Shade, compaction, poor drainage, low fertility and acidic soil all favor moss over grass. Moss killers only buy time if those causes aren't fixed. Note where moss is worst now so you can plan pruning for more light, aeration, or a switch to a shade-tolerant groundcover.
Leaves left on the lawn through the rainy season smother the grass and create the damp, shaded conditions moss loves. Rake or mow them up every week or two while they are falling, and put them to use on garden beds or in the compost.
Trees, shrubs, perennials and dahlias
Per OSU Extension, fall planting offers long-term benefits for trees, shrubs and perennials. Rain does most of the watering, and roots grow through the mild west-side winter. Divide crowded perennials such as daylilies and hostas now as well.
Dahlias: OSU Extension covers both approaches to overwintering. In well-drained west-side soils, many gardeners cut the stalks after frost blackens them and leave the tubers in the ground under a thick mulch. In heavy, wet clay or colder sites, dig the tubers after frost and store them cool and frost-free.
East of the Cascades
East of the Cascades (zones 5–7: Spokane, Yakima, the Tri-Cities, Bend), October brings hard freezes, not rain:
- Winterize irrigation before the first hard freeze. Drain or blow out lines and protect backflow devices, as WSU recommends.
- Plant garlic early enough for roots to establish before the ground freezes, and mulch it more heavily than you would on the west side.
- Water trees and evergreens deeply before the ground freezes if fall has been dry. University of Idaho Extension warns that drought-stressed trees and shrubs go into winter at a disadvantage.
- Harvest tender crops ahead of killing frosts. Planting windows close weeks earlier here than in the Willamette Valley or Puget Sound.
Common mistakes
| Mistake | Consequence | Correct approach |
|---|---|---|
| Waiting until spring to deal with slugs | Fall survivors lay eggs that hatch into a bigger spring population | Trap, hand-pick and bait in fall, and remove daytime hiding spots |
| Leaving vegetable beds bare over winter | Rain compacts and crusts the soil and leaches nutrients | Cover with leaves or straw, or sow a cover crop on time next September |
| Planting garlic or bulbs in waterlogged clay | Cloves and bulbs rot over winter | Plant in raised or well-drained beds and mulch |
| Leaving green tomatoes on the vine into the fall rains | Late blight and split, rotting fruit | Harvest before frost and ripen indoors |
| Treating lawn moss without fixing the cause | Moss returns every winter | Address shade, compaction, drainage and fertility |
Frequently asked
When should I plant garlic in western Oregon and Washington?
OSU Extension calls fall the best time to plant garlic. In the western lowlands, mid-October is typical, once the first rains have softened the soil. East of the Cascades, plant earlier so roots can establish before the ground freezes.
Should I dig up my dahlias in the Pacific Northwest?
It depends on your soil. In well-drained west-side beds, many gardeners leave tubers in the ground under heavy mulch. In wet clay or colder areas, dig them after frost and store them cool and frost-free.
Why are slugs worse in my fall garden?
Returning rain wakes them up just as tender fall transplants go in. OSU Extension says fall control matters because it removes slugs before they lay the eggs that hatch next spring.
Is it too late to plant a cover crop in October?
Seeds sown this late often don't make enough growth before winter to protect the soil. Mulching bare beds with leaves or straw is the more reliable choice now.
Sources
- October Garden Calendar (EM 9611), OSU Extension
- Fall is the best time to plant garlic in Oregon, OSU Extension
- Fall and spring are prime times to battle garden slugs, OSU Extension
- Fall and Winter Vegetable Gardens for Western Washington, WSU Extension Snohomish County
- How to manage moss in Oregon lawns, OSU Extension
- Fall in love with colorful, dazzling dahlias, OSU Extension
- Winterizing Irrigation Systems, Washington State University
- Helping Your Drought-Stressed Trees and Shrubs Through the Winter, University of Idaho Extension