Now
21°C · Clear
Today
22° / 11°
Soil 6 cm
17°C
First frost
~77 days (Nov 24)
Gardening in Seattle
AI field guide · refreshed weeklySeattle Gardening: Early Fall Planting & Harvest (Sept 8–14)
Zone 9a, first fall frost Nov 24 (77 days away). Soil at 17°C (63°F) is ideal for cool-season crops—still warm enough for germination, cool enough to favor leafy greens and brassicas over bolting. You're in the sweet spot: plant now for October–November harvest before hard freeze.
Sow outdoors now
Spinach (Bloomsdale, Space or Tyee)
Direct sow 1 cm (0.4 in) deep, 10 cm (4 in) apart. Germinates in 7–10 days at 17°C; ready to harvest in 40–50 days, well before November frost.
Arugula (Roquette)
Scatter seed 0.5 cm (0.2 in) deep, thin to 5 cm (2 in). Peppery leaves in 30 days; succession-sow every 2 weeks through October for continuous harvest.
Mâche (Corn Salad)
Sow 0.5 cm deep, 5 cm apart. Cold-hardy, germinates slowly (14–21 days) but thrives as temperatures drop; harvest November–December.
Radish (Cherry Belle, French Breakfast)
Direct sow 1 cm deep, 5 cm apart. Ready in 25–30 days; successive sowings every 10 days extend harvest into November.
Kale (Lacinato, Winterbor)
Direct sow 1 cm deep, thin to 15 cm (6 in). Slow to mature (60+ days) but cold-sweetens after frost; plant now for late-fall and winter harvest.
Start indoors now
Cabbage (January King, Savoy)
Sow in pots indoors; transplant seedlings outdoors in 3–4 weeks (early October) for November harvest before hard freeze.
Broccoli (Arcadia, Belstar)
Start indoors now; transplant at 4–6 weeks (mid-October). Needs 60–70 days to head; timing is tight but doable with early planting.
Lettuce (Winter Density, Buttercrunch)
Sow indoors in modules; transplant in 2–3 weeks for faster establishment than direct seeding in cool soil.
Harvest now
Tomatoes (all types)
Pick ripe and near-ripe fruit before nights drop below 10°C (50°F); ripen indoors on a sunny windowsill or in a paper bag with an apple.
Beans (bush and pole)
Harvest pods before frost; plants will die at first hard freeze. Pick regularly to encourage final flushes.
Summer squash & zucchini
Gather all fruit; frost will kill plants within weeks. Leave mature squash on vine to cure for storage.
Herbs (basil, cilantro, parsley)
Cut and dry or freeze basil before first frost kills it; cilantro and parsley tolerate light frost and will regrow in cool weather.
Tasks this week
- Clear spent summer crops (tomatoes, peppers, beans) to reduce disease and make room for fall plantings.
- Amend beds with 5 cm (2 in) compost or aged manure; cool soil temps slow decomposition, so work it in now.
- Water new sowings gently and keep soil consistently moist until germination; no rain forecast this week.
- Set up row covers or cloches over tender seedlings if frost threatens earlier than Nov 24.
- Stake or trellis fall brassicas (cabbage, broccoli) if wind gusts reach 14–16 km/h (9–10 mph) later in the week.
Watch out for
- Slugs and snails thrive in Seattle's damp fall; hand-pick at dawn or dusk, or use beer traps and copper tape on raised beds.
- Powdery mildew and downy mildew favor cool, humid nights (86% humidity today)—space plants well, water at soil level, remove infected leaves.
- Cabbage moths and flea beetles are still active; use row covers over brassicas and leafy greens immediately after planting.
The gardening note for Seattle, every week
One email, Sunday evening. Unsubscribe anytime.