Frost Dates & Planting Calendar for Altamont, OR
Plan your garden around Altamont, OR's typical frost-free growing season, using NOAA climate normals and a 42-crop planting calendar built for this location.
Last Spring Frost
June 9
Safe Jun 26
Typical Jun 9
Risky May 22
First Fall Frost
September 18
Safe Sep 4
Typical Sep 18
Risky Oct 1
Growing Season
99 days
Typical last frost to typical first frost.
USDA Hardiness Zone
Zone 6b
A classic four-season climate with cold winters and a solid summer growing season.
Data: NOAA station KLAMATH FALLS INTL AP, OR US, 6.7 km away.
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days until the typical last spring frost
Monthly Temperatures
Avg. high
Avg. temp
Avg. low
Planting Calendar
| Crop | Start indoors | Direct sow | Transplant | Fall planting | Maturity | Notes |
|---|---|---|---|---|---|---|
| Tomato | Apr 14 – Apr 28 | — | Jun 16 – Jun 23 | — | 60–85 days | Start indoors 6-8 weeks before last frost; transplant out 1-2 weeks after last frost once soil has warmed. |
| Pepper | Mar 31 – Apr 14 | — | Jun 16 – Jun 30 | — | 60–90 days | Slow to germinate; start indoors 8-10 weeks before last frost. Transplant only once nights stay above 55F, 1-3 weeks after last frost. |
| Eggplant | Mar 31 – Apr 14 | — | Jun 23 – Jun 30 | — | 65–85 days | Warm-season crop, similar timing to pepper; needs consistently warm soil (65F+) to transplant. |
| Cucumber | May 12 – May 19 | Jun 16 – Jun 23 | Jun 16 – Jun 23 | — | 50–65 days | Can be started indoors 3-4 weeks before transplanting, or direct-sown 1-2 weeks after last frost once soil is warm. |
| Zucchini | May 19 – May 26 | Jun 16 – Jun 30 | Jun 16 – Jun 23 | — | 45–55 days | Fast-growing squash; direct sow 1-3 weeks after last frost, or start indoors 2-3 weeks early for a head start. |
| Winter Squash | May 12 – May 19 | Jun 16 – Jun 30 | Jun 16 – Jun 23 | — | 80–110 days | Long season; direct sow after soil warms, or start indoors 3-4 weeks before last frost in short-season climates. |
| Pumpkin | — | Jun 16 – Jun 30 | — | — | 90–120 days | Direct sow 1-3 weeks after last frost; back-time from your first fall frost so the 90-120 day maturity window lands before it. |
| Watermelon | May 12 – May 19 | — | Jun 23 – Jun 30 | — | 70–90 days | Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost. |
| Cantaloupe | May 12 – May 19 | — | Jun 23 – Jun 30 | — | 70–90 days | Same warm-soil requirements as watermelon; avoid disturbing roots when transplanting. |
| Corn | — | Jun 9 – Jun 23 | — | — | 60–100 days | Direct sow at last frost to 2 weeks after, once soil reaches 60F; does not transplant well. Succession sow every 2 weeks. |
| Green Bean | — | Jun 9 – Jun 23 | — | — | 50–65 days | Direct sow at last frost to 2 weeks after, once soil has warmed; frost-tender, do not rush. |
| Pea | — | Apr 28 – May 12 | — | — | 55–70 days | Cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Lettuce | — | May 12 – May 26 | — | Jul 24 – Aug 7 | 45–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. Also transplantable from indoor starts. |
| Spinach | — | Apr 28 – May 12 | — | Jul 24 – Aug 7 | 40–50 days | Very cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Kale | — | May 12 – May 26 | — | Jul 10 – Jul 24 | 50–65 days | Cold-hardy; direct sow 2-4 weeks before last frost or start indoors for earlier transplants. |
| Arugula | — | May 12 – May 26 | — | Aug 7 – Aug 14 | 30–40 days | Fast-growing, cold-tolerant green; direct sow 2-4 weeks before last frost, succession sow every 2-3 weeks. |
| Swiss Chard | — | May 19 – Jun 2 | — | — | 50–60 days | Fairly cold-hardy; direct sow 1-3 weeks before last frost. Tolerates light frost in fall too. |
| Broccoli | Apr 21 – May 5 | — | May 19 – May 26 | Jul 17 – Jul 24 | 55–80 days | Start indoors 5-7 weeks before last frost; transplant out 2-3 weeks before last frost (hardens off to light frost). |
| Cauliflower | Apr 21 – May 5 | — | May 26 – Jun 2 | Jul 10 – Jul 17 | 55–85 days | Fussier than broccoli about temperature swings; start indoors 5-7 weeks before last frost, transplant 1-2 weeks before last frost. |
| Cabbage | Apr 21 – May 5 | — | May 12 – May 26 | Jul 10 – Jul 24 | 60–100 days | Cold-hardy; start indoors 5-7 weeks before last frost, transplant 2-4 weeks before last frost. |
| Brussels Sprouts | Apr 21 – May 5 | — | May 19 – Jun 2 | — | 90–110 days | Long-season crop best timed to mature after a light fall frost for sweetest flavor; start indoors 5-7 weeks before last frost. |
| Carrot | — | May 12 – May 26 | — | Jun 26 – Jul 10 | 60–80 days | Direct sow only (does not transplant); sow 2-4 weeks before last frost, as soon as soil can be worked. |
| Beet | — | May 12 – May 26 | — | Jul 10 – Jul 24 | 50–65 days | Direct sow 2-4 weeks before last frost; tolerates light frost. |
| Radish | — | May 5 – May 19 | — | Aug 7 – Aug 21 | 22–30 days | Very fast and cold-hardy; direct sow 3-5 weeks before last frost, as soon as soil can be worked. |
| Turnip | — | May 12 – May 26 | — | Jul 10 – Jul 24 | 40–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. |
| Onion | Mar 31 – Apr 14 | — | May 12 – May 26 | — | 90–120 days | Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings. |
| Garlic | — | — | — | Aug 21 – Sep 4 | 240–270 days | Fall-planted crop only; not planted in spring in most climates. |
| Potato | — | May 12 – May 26 | — | — | 70–120 days | Plant seed potatoes 2-4 weeks before last frost, as soon as soil can be worked and is above 45F; light frost on emerging foliage is usually tolerated. |
| Sweet Potato | — | — | Jun 23 – Jul 7 | — | 90–120 days | Set out slips 2-4 weeks after last frost once soil is thoroughly warm (65F+); very frost/cold sensitive. |
| Asparagus | — | — | May 12 – May 26 | — | 730–1095 days | Perennial; plant crowns 2-4 weeks before last frost as soon as soil can be worked. Takes 2-3 years to full production. |
| Crop | Start indoors | Direct sow | Transplant | Fall planting | Maturity | Notes |
|---|---|---|---|---|---|---|
| Basil | Apr 28 – May 5 | — | Jun 16 – Jun 23 | — | 50–70 days | Very frost/cold sensitive; start indoors 5-6 weeks before last frost, transplant only after all danger of frost (1-2 weeks after) and nights stay warm. |
| Cilantro | — | May 19 – Jun 2 | — | Jul 24 – Aug 7 | 45–70 days | Cool-season, bolts in heat; direct sow 1-3 weeks before last frost, succession sow through spring. |
| Parsley | Apr 14 – Apr 28 | — | May 26 – Jun 2 | — | 70–90 days | Slow to germinate; start indoors 6-8 weeks before last frost, transplant 1-2 weeks before last frost (biennial, cold-tolerant). |
| Dill | — | May 19 – Jun 2 | — | — | 40–60 days | Taprooted, does not transplant well; direct sow 1-3 weeks before last frost, succession sow through summer. |
| Oregano | Apr 14 – Apr 28 | — | Jun 9 – Jun 16 | — | 80–90 days | Perennial herb; start indoors 6-8 weeks before last frost, transplant around/just after last frost date. |
| Thyme | Apr 14 – Apr 28 | — | Jun 9 – Jun 16 | — | 85–95 days | Perennial herb, slow from seed; start indoors 6-8 weeks before last frost, transplant around/after last frost. |
| Crop | Start indoors | Direct sow | Transplant | Fall planting | Maturity | Notes |
|---|---|---|---|---|---|---|
| Sunflower | — | Jun 16 – Jun 30 | — | — | 70–100 days | Direct sow 1-3 weeks after last frost once soil has warmed; taprooted, resents transplanting. |
| Zinnia | May 12 – May 19 | Jun 16 – Jun 30 | Jun 16 – Jun 23 | — | 60–70 days | Frost-tender; direct sow 1-3 weeks after last frost, or start indoors 3-4 weeks early for earlier blooms. |
| Marigold | Apr 28 – May 12 | — | Jun 16 – Jun 23 | — | 45–60 days | Frost-tender; start indoors 4-6 weeks before last frost, transplant after all frost danger has passed. |
| Cosmos | May 12 – May 19 | Jun 16 – Jun 30 | Jun 16 – Jun 23 | — | 60–90 days | Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early. |
| Nasturtium | — | Jun 16 – Jun 30 | — | — | 50–65 days | Frost-tender, resents root disturbance; direct sow 1-3 weeks after last frost once soil has warmed. |
| Dahlia | — | — | Jun 16 – Jun 30 | — | 90–120 days | Plant tubers 1-3 weeks after last frost once soil is warm (60F+); very frost-sensitive. |
Date ranges are estimates based on university extension guidelines and this city's NOAA frost normals — not a guarantee. Scroll to see all columns on narrow screens.
Frequently Asked Questions
When is the last frost in Altamont, OR?
Based on 1991–2020 NOAA climate normals for the KLAMATH FALLS INTL AP, OR US station, the last spring frost in Altamont typically falls around June 9. A cautious gardener might wait until June 26 (only a 10% chance of a later frost), while May 22 marks an earlier, higher-risk planting date.
When is the first frost in Altamont, OR in fall?
The first fall frost in Altamont typically arrives around September 18. To stay safe, assume frost could start as early as September 4; in milder years it can hold off until October 1.
How long is the growing season in Altamont, OR?
Altamont's average frost-free growing season is about 99 days, running from the typical last spring frost (June 9) to the typical first fall frost (September 18).
What USDA hardiness zone is Altamont, OR in?
Altamont, OR is in USDA plant hardiness zone 6b, per the USDA's 2023 Plant Hardiness Zone Map. A classic four-season climate with cold winters and a solid summer growing season.