Last Frost Date

Planting planner: Hillsboro, Oregon

Typical last spring frost April 16 (1 spring in 10 later than May 3). Typical first fall frost October 23 (1 fall in 10 earlier than October 3). Growing season about 191 days.

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Frost likely Frost possible Frost unlikely Frost is likely until March 25 and fades out by May 3. It is unlikely from then until October 3, and likely again after November 18. The dashed lines are the typical dates, April 16 and October 23.

January

  • January 29 to February 26: Broccoli and cabbage (start seeds indoors)

February

  • February 12 to March 12: Cauliflower (start seeds indoors)
  • February 26 to March 19: Eggplant (start seeds indoors)

March

  • March 5 to 19: Peppers (start seeds indoors)
  • March 12 to 26: Tomatoes (start seeds indoors)
  • March 19 to April 2: Peas, spinach, lettuce, radishes, onion sets, turnips (sow outdoors)
  • March 19 to April 2: Broccoli and cabbage (plant out)

April

  • April 2 to 16: Beets, carrots, potatoes, Swiss chard (plant outdoors)
  • April 2 to 16: Cauliflower (plant out)
  • April 16: Snap beans, sweet corn, cucumbers, summer squash (sow outdoors)
  • April 30: Tomatoes, peppers, eggplant (plant out)
  • April 30: Melons, winter squash, pumpkins, lima beans (sow outdoors)

May

  • May 28 to June 11: Cabbage for fall (start seeds)

June

  • June 17 to July 1: Broccoli for fall (start seeds)

July

  • July 27: Snap beans for fall (last date to sow)
  • July 31: Carrots for fall (last date to sow)

August

  • August 1: Cucumbers for fall (last date to sow)
  • August 5: Peas for fall (last date to sow)
  • August 6: Summer squash for fall (last date to sow)
  • August 10: Leaf lettuce and beets for fall (last date to sow)
  • August 20: Turnips and kohlrabi for fall (last date to sow)
  • August 30: Spinach for fall (last date to sow)

September

  • September 9: Radishes for fall (last date to sow)

October

  • October 3: Tomatoes, peppers, squash, melons, cucumbers (watch the forecast)

November

  • November 19 to 26: Garlic (plant cloves)

December

Nothing to start this month.

Dates from NOAA's 1991 to 2020 climate normals for Portland-Hillsboro Airport (station USW00094261), 1 mile from the center of Hillsboro. Planting rules: Colorado State University Extension GardenNotes #720 (spring), Virginia Cooperative Extension 426-334 (fall crops), University of Minnesota Extension (garlic). Spring bulbs: plant when the soil has cooled to about 50 to 55°F, until a couple of weeks before the ground freezes (University of Wisconsin–Madison Extension). Full details: https://lastfrostdate.com/frost-dates/oregon/hillsboro/

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