USDA Hardiness Zone 8b
Frost Dates for 97446 — Harrisburg, Oregon
Averages from Eugene Mahlon Sweet Ap, Or US, the nearest reporting station, 11.6 miles away.
Plant tender crops after April 11, and expect the first autumn freeze around October 23. That leaves about 196 frost-free days.
- Last spring frost
- April 11
- First fall frost
- October 23
- Growing season
- 196 days
- Hardiness zone
- 8b
50% probability
50% probability
frost-free
15 to 20°F annual low
Planting calendar for 97446
| When | What to do |
|---|---|
| January 31 – February 14 | Start peppers and aubergines indoors They need eight to ten weeks under lights before they can go out. |
| February 14 – February 28 | Start tomatoes indoors Six to eight weeks gives a transplant big enough to set fruit early. |
| March 14 – March 28 | Sow peas, spinach, lettuce, radish outdoors These tolerate light frost and prefer to germinate in cool soil. |
| April 11 onward | Transplant tomatoes, peppers, basil, squash, cucumbers The average last freeze has passed — still watch the actual forecast. |
| by July 31 | Sow the autumn crop of carrots, beets and brassicas They need about twelve weeks to size up before growth stops. |
| by October 9 | Harvest tender crops, or be ready to cover them A first freeze two weeks early is well within normal variation. |
| October 23 onward | Plant garlic, mulch beds, lift tender bulbs Garlic wants a cold spell; bare soil loses structure over winter. |
What these dates mean
Wait until after April 11 to put tender plants — tomatoes, peppers, basil, squash — in the ground. That is the date by which half of years in Harrisburg, Oregon are past their last freeze. Harvest before October 23, which leaves roughly 196 frost-free days.
ZIP 97446 sits in USDA hardiness zone 8b, meaning the average coldest night of the year falls between 15 to 20°F. Zone decides what survives the winter; frost dates decide when to plant each spring. They are different questions, and a plant can pass one and fail the other.
These are thirty-year NOAA averages for 1991–2020, not a forecast. Any individual year can frost two to three weeks either side of these dates, so check the actual forecast before planting out.