When to plant arugula in Portland, Maine
September 1 – September 15
Fall planting · typical Portland yearClimate basis: NOAA station Portland INTL Jetport, ME (USW00014764), 2 mi (4 km) from downtown Portland (ZCTA 04101 centroid), elevation 45 ft, on the 1991–2020 climate normals. Plant arugula for fall from approximately the dates above, anchored to the median first fall 32°F freeze (October 15). One year in ten still freezes after May 7.
The Portland year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to May 7
Every method, with its sources
Fall planting
Sep 1 – Sep 15Cornell Garden-Based Learning caps successive arugula sowings at "about a month before your average first frost date", so the fall sowing window is the 14 days ending at that cutoff (first fall frost minus 44 to minus 30 days); Wisconsin Horticulture agrees arugula tolerates frost but gives no numeric offset. Anchored to the median first fall freeze (Oct 15). Cornell University Garden-Based Learning (Cornell Cooperative Extension)
Start seeds indoors
Not calculatedThe cited extension guides do not time an indoor seed-starting window for this crop.
Transplant outdoors
Not calculatedThe cited extension guides do not time an outdoor transplanting window for this crop.
Direct-sow outdoors
Not calculatedCornell times spring arugula only by soil condition — "Plant as soon as soil can be worked in spring." — which is not an offset from a freeze date, so no spring window is computed here. The window above is the last succession sowing before the first fall freeze.
Variety assumption: No spring window is published: every extension page fetched gives only soil-workability language ("as soon as soil can be worked") or the unquantified "several weeks before the last frost", neither of which yields an honest numeric offset, so only the frost-anchored fall cutoff is encoded.
These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.
Crop rule sources (1)
- Cornell University Garden-Based Learning (Cornell Cooperative Extension): Arugula growing guide (accessed 2026-07-25)"Make new plantings every 2 to 3 weeks for a continuous supply until about a month before your average first frost date."