When to plant fava bean in Seattle

In Seattle, typical last spring frost is March 25 and typical first fall frost is November 20. Typical last spring frost: March 25. Fava bean in Seattle is a good fit outdoors. The suitable growing window of 133 days covers the 80–110 days this plant usually needs.

Fava bean

How to grow Fava bean Seattle climate Weekly temperatures and windows

Where are you growing?

Comfortable

Comfortable in greenhouse

Comfortable in a cold frame

Fava bean in Seattle is a good fit outdoors. The suitable growing window of 133 days covers the 80–110 days this plant usually needs.

When to plantMarch 3 – August 8

Harvest: May 22 – December 1
Season vs crop: 133 grow days vs 80–110 needed
Typical frost (last spring – first fall): March 25 – November 20

Fava bean in Seattle is a good fit outdoors. The suitable growing window of 133 days covers the 80–110 days this plant usually needs.

Planting conditions

Direct sow
Harvest

Local activity windows for this place and growing method. Blue fill is usually too cold for this plant. Dashed lines are typical last and first frost.

Suitable growing days in a row133

Days to harvest80–110 days from seed

Mar 3 – Aug 8

Direct sow

May 22 – Dec 1

Harvest

Activity	Window	Notes
Direct sow	Mar 3 – Aug 8	Plant outdoors in this window.
Harvest	May 22 – Dec 1	Expected harvest from typical days to harvest.

Direct sow
Harvest

Blue fill is usually too cold for this plant. Dashed lines are typical last and first frost (35 seasons (1991–2025)). Adjust a week or two for your conditions.

Planting and growing across the year

Planting is the sow / plant-out window. Growing is daytime air versus this plant’s ideal (15 – 21 °C59 – 70 °F15 – 21 °C (59 – 70 °F)) and tolerable (4 – 24 °C39 – 75 °F4 – 24 °C (39 – 75 °F)) ranges.

Ideal / plantable
Tolerable
Too cold
Too hot
Outside window

Planting uses sow / plant-out rules; growing shows daytime air against this plant’s ideal and tolerable ranges.

Key dates

Typical last spring frostMarch 25

Low-risk last spring frostApril 14

Typical first fall frostNovember 20

Low-risk first fall frostOctober 29

Frost-free days239

Outdoor sow dateMarch 3

Direct sow windowMarch 3 – August 8

Suitable growing windowMarch 3 – July 13 (133 days)

Expected harvestMay 22 – December 1

How these dates are judged

Ideal conditions: Daytime air from 15 – 21 °C59 – 70 °F15 – 21 °C (59 – 70 °F).
Suitable conditions: Daytime air from 4 – 24 °C39 – 75 °F4 – 24 °C (39 – 75 °F).
Last frost and first frost: Typical spring and fall frost dates for Seattle, shown in the key dates.
Days to harvest: 80–110 days from seed, from typical days to harvest.
Sowing window: Dated sow and harvest bars use frost dates, soil minima, night limits, and last-sow count-back from typical crop timing. Air ratings on the weekly chart colour only weeks inside that same window — see weekly temperatures and windows.

Other plants for Seattle

Calculated by Plan & Plant. Method. Data 35 seasons (1991–2025).

Frost and suitability dates are typical figures from climate statistics.

Based on 35 years (1991–2025) of ERA5-Land data from Open-Meteo, for an area of about 10 km. Typical dates, not a guarantee.

Dates for Seattle use ERA5-Land cell 47.60, -122.30. How we calculated this · Algorithm 2026-10-season-10.

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