Now
23°C · Clear
Today
24° / 12°
Soil 6 cm
18°C
First frost
~72 days (Nov 19)
Gardening in Portland
AI field guide · refreshed weeklyPortland Gardening: Early September – Sow Cool-Season Crops, Extend Fall Harvests
You're in zone 8b with 72 days until the average first frost (Nov 19). Soil is still warm at 18°C (64°F)—perfect for germinating fall crops. Plant now and you'll harvest before hard freezes arrive. Spring frost typically hits Apr 6, giving you a long growing season ahead.
Sow outdoors now
Spinach (Space or Bloomsdale)
Direct sow now; germinates quickly in 18°C soil and tolerates light frosts. Harvest in 40–50 days before November.
Arugula (Roquette)
Sow thickly for fast turnover; ready in 30–40 days and cold-hardy to −3°C (25°F). Succession sow every 2 weeks through October.
Mâche (Corn Salad)
Extremely cold-hardy; sow now for winter harvests. Germinates slowly but thrives in cool, damp Portland falls.
Radish (Cherry Belle or Watermelon)
Ready in 25–30 days; sow in blocks to deter flea beetles. Plant by mid-September for best results.
Kale (Winterbor or Lacinato)
Sow now for transplanting in 4–6 weeks; cold improves flavor. Harvest through winter in zone 8b.
Start indoors now
Broccoli (Arcadia or De Cicco)
Start seeds indoors now; transplant in 4–5 weeks for October harvest before hard frost.
Cabbage (January King or Tundra)
Sow indoors for late-season transplants; these varieties store well and tolerate Portland winters.
Leeks (King Richard or Varna)
Start now for transplanting in 6 weeks; they'll grow through fall and winter, ready for harvest by spring.
Harvest now
Tomatoes (all varieties)
Nights are cooling; pick ripe and near-ripe fruit now. Ripen indoors or make salsa before frost arrives in 10 weeks.
Beans (bush and pole)
Harvest regularly to encourage final flushes before the first frost in mid-November.
Peppers (sweet and hot)
Pick mature peppers; plants slow as temperatures drop. Green peppers will ripen indoors if picked now.
Summer squash and zucchini
Harvest daily while productive; plants decline as nights cool. Remove spent vines by late September.
Tasks this week
- Deadhead flowers and remove spent annuals to redirect energy and reduce pest habitat.
- Water deeply 2–3 times this week (dry forecast); fall crops need consistent moisture to germinate.
- Mulch newly sown beds with 2–3 cm (1 in) compost to retain warmth and moisture.
- Scout for aphids and spider mites on remaining warm-season crops; spray with neem oil if needed.
- Cut back perennials after flowering; leave ornamental grasses for winter structure and wildlife.
Watch out for
- Slugs thrive in Portland's damp fall; hand-pick or use beer traps around new seedlings.
- Powdery mildew appears on squash and beans as humidity rises—thin foliage for airflow.
- Flea beetles attack young brassicas and arugula; use row covers or neem oil on transplants.
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