Frost Dates & Planting Calendar for College, AK
Plan your garden around College, AK's typical frost-free growing season, using NOAA climate normals and a 42-crop planting calendar built for this location.
Last Spring Frost
May 18
Safe Jun 1
Typical May 18
Risky May 7
First Fall Frost
September 6
Safe Aug 24
Typical Sep 6
Risky Sep 20
Growing Season
111 days
Typical last frost to typical first frost.
USDA Hardiness Zone
Zone 2b
Extreme cold winters — stick to the hardiest perennials and treat most vegetables as annuals started well after the ground thaws.
Data: NOAA station COLLEGE OBSY, AK US, 2.2 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 | Mar 23 – Apr 6 | — | May 25 – Jun 1 | — | 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 9 – Mar 23 | — | May 25 – Jun 8 | — | 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 9 – Mar 23 | — | Jun 1 – Jun 8 | — | 65–85 days | Warm-season crop, similar timing to pepper; needs consistently warm soil (65F+) to transplant. |
| Cucumber | Apr 20 – Apr 27 | May 25 – Jun 1 | May 25 – Jun 1 | — | 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 | Apr 27 – May 4 | May 25 – Jun 8 | May 25 – Jun 1 | — | 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 | Apr 20 – Apr 27 | May 25 – Jun 8 | May 25 – Jun 1 | — | 80–110 days | Long season; direct sow after soil warms, or start indoors 3-4 weeks before last frost in short-season climates. |
| Pumpkin | — | May 25 – Jun 8 | — | — | 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 | Apr 20 – Apr 27 | — | Jun 1 – Jun 8 | — | 70–90 days | Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost. |
| Cantaloupe | Apr 20 – Apr 27 | — | Jun 1 – Jun 8 | — | 70–90 days | Same warm-soil requirements as watermelon; avoid disturbing roots when transplanting. |
| Corn | — | May 18 – Jun 1 | — | — | 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 | — | May 18 – Jun 1 | — | — | 50–65 days | Direct sow at last frost to 2 weeks after, once soil has warmed; frost-tender, do not rush. |
| Pea | — | Apr 6 – Apr 20 | — | — | 55–70 days | Cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Lettuce | — | Apr 20 – May 4 | — | Jul 12 – Jul 26 | 45–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. Also transplantable from indoor starts. |
| Spinach | — | Apr 6 – Apr 20 | — | Jul 12 – Jul 26 | 40–50 days | Very cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Kale | — | Apr 20 – May 4 | — | Jun 28 – Jul 12 | 50–65 days | Cold-hardy; direct sow 2-4 weeks before last frost or start indoors for earlier transplants. |
| Arugula | — | Apr 20 – May 4 | — | Jul 26 – Aug 2 | 30–40 days | Fast-growing, cold-tolerant green; direct sow 2-4 weeks before last frost, succession sow every 2-3 weeks. |
| Swiss Chard | — | Apr 27 – May 11 | — | — | 50–60 days | Fairly cold-hardy; direct sow 1-3 weeks before last frost. Tolerates light frost in fall too. |
| Broccoli | Mar 30 – Apr 13 | — | Apr 27 – May 4 | Jul 5 – Jul 12 | 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 | Mar 30 – Apr 13 | — | May 4 – May 11 | Jun 28 – Jul 5 | 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 | Mar 30 – Apr 13 | — | Apr 20 – May 4 | Jun 28 – Jul 12 | 60–100 days | Cold-hardy; start indoors 5-7 weeks before last frost, transplant 2-4 weeks before last frost. |
| Brussels Sprouts | Mar 30 – Apr 13 | — | Apr 27 – May 11 | — | 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 | — | Apr 20 – May 4 | — | Jun 14 – Jun 28 | 60–80 days | Direct sow only (does not transplant); sow 2-4 weeks before last frost, as soon as soil can be worked. |
| Beet | — | Apr 20 – May 4 | — | Jun 28 – Jul 12 | 50–65 days | Direct sow 2-4 weeks before last frost; tolerates light frost. |
| Radish | — | Apr 13 – Apr 27 | — | Jul 26 – Aug 9 | 22–30 days | Very fast and cold-hardy; direct sow 3-5 weeks before last frost, as soon as soil can be worked. |
| Turnip | — | Apr 20 – May 4 | — | Jun 28 – Jul 12 | 40–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. |
| Onion | Mar 9 – Mar 23 | — | Apr 20 – May 4 | — | 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 9 – Aug 23 | 240–270 days | Fall-planted crop only; not planted in spring in most climates. |
| Potato | — | Apr 20 – May 4 | — | — | 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 1 – Jun 15 | — | 90–120 days | Set out slips 2-4 weeks after last frost once soil is thoroughly warm (65F+); very frost/cold sensitive. |
| Asparagus | — | — | Apr 20 – May 4 | — | 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 6 – Apr 13 | — | May 25 – Jun 1 | — | 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 | — | Apr 27 – May 11 | — | Jul 12 – Jul 26 | 45–70 days | Cool-season, bolts in heat; direct sow 1-3 weeks before last frost, succession sow through spring. |
| Parsley | Mar 23 – Apr 6 | — | May 4 – May 11 | — | 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 | — | Apr 27 – May 11 | — | — | 40–60 days | Taprooted, does not transplant well; direct sow 1-3 weeks before last frost, succession sow through summer. |
| Oregano | Mar 23 – Apr 6 | — | May 18 – May 25 | — | 80–90 days | Perennial herb; start indoors 6-8 weeks before last frost, transplant around/just after last frost date. |
| Thyme | Mar 23 – Apr 6 | — | May 18 – May 25 | — | 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 | — | May 25 – Jun 8 | — | — | 70–100 days | Direct sow 1-3 weeks after last frost once soil has warmed; taprooted, resents transplanting. |
| Zinnia | Apr 20 – Apr 27 | May 25 – Jun 8 | May 25 – Jun 1 | — | 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 6 – Apr 20 | — | May 25 – Jun 1 | — | 45–60 days | Frost-tender; start indoors 4-6 weeks before last frost, transplant after all frost danger has passed. |
| Cosmos | Apr 20 – Apr 27 | May 25 – Jun 8 | May 25 – Jun 1 | — | 60–90 days | Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early. |
| Nasturtium | — | May 25 – Jun 8 | — | — | 50–65 days | Frost-tender, resents root disturbance; direct sow 1-3 weeks after last frost once soil has warmed. |
| Dahlia | — | — | May 25 – Jun 8 | — | 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 College, AK?
Based on 1991–2020 NOAA climate normals for the COLLEGE OBSY, AK US station, the last spring frost in College typically falls around May 18. A cautious gardener might wait until June 1 (only a 10% chance of a later frost), while May 7 marks an earlier, higher-risk planting date.
When is the first frost in College, AK in fall?
The first fall frost in College typically arrives around September 6. To stay safe, assume frost could start as early as August 24; in milder years it can hold off until September 20.
How long is the growing season in College, AK?
College's average frost-free growing season is about 111 days, running from the typical last spring frost (May 18) to the typical first fall frost (September 6).
What USDA hardiness zone is College, AK in?
College, AK is in USDA plant hardiness zone 2b, per the USDA's 2023 Plant Hardiness Zone Map. Extreme cold winters — stick to the hardiest perennials and treat most vegetables as annuals started well after the ground thaws.