Frost Dates & Planting Calendar for Sault Ste. Marie, MI
Plan your garden around Sault Ste. Marie, MI's typical frost-free growing season, using NOAA climate normals and a 42-crop planting calendar built for this location.
Last Spring Frost
May 9
Safe May 27
Typical May 9
Risky Apr 27
First Fall Frost
October 11
Safe Sep 26
Typical Oct 11
Risky Oct 26
Growing Season
151 days
Typical last frost to typical first frost.
USDA Hardiness Zone
Zone 4b
Very cold winters, focus on short-season varieties and cold-hardy perennials.
Data: NOAA station SAULT STE MARIE SANDERSON FLD, MI US, 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 14 – Mar 28 | — | May 16 – May 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 | Feb 28 – Mar 14 | — | May 16 – May 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 | Feb 28 – Mar 14 | — | May 23 – May 30 | — | 65–85 days | Warm-season crop, similar timing to pepper; needs consistently warm soil (65F+) to transplant. |
| Cucumber | Apr 11 – Apr 18 | May 16 – May 23 | May 16 – May 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 | Apr 18 – Apr 25 | May 16 – May 30 | May 16 – May 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 | Apr 11 – Apr 18 | May 16 – May 30 | May 16 – May 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 | — | May 16 – May 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 | Apr 11 – Apr 18 | — | May 23 – May 30 | — | 70–90 days | Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost. |
| Cantaloupe | Apr 11 – Apr 18 | — | May 23 – May 30 | — | 70–90 days | Same warm-soil requirements as watermelon; avoid disturbing roots when transplanting. |
| Corn | — | May 9 – May 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 | — | May 9 – May 23 | — | — | 50–65 days | Direct sow at last frost to 2 weeks after, once soil has warmed; frost-tender, do not rush. |
| Pea | — | Mar 28 – Apr 11 | — | — | 55–70 days | Cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Lettuce | — | Apr 11 – Apr 25 | — | Aug 16 – Aug 30 | 45–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. Also transplantable from indoor starts. |
| Spinach | — | Mar 28 – Apr 11 | — | Aug 16 – Aug 30 | 40–50 days | Very cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Kale | — | Apr 11 – Apr 25 | — | Aug 2 – Aug 16 | 50–65 days | Cold-hardy; direct sow 2-4 weeks before last frost or start indoors for earlier transplants. |
| Arugula | — | Apr 11 – Apr 25 | — | Aug 30 – Sep 6 | 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 18 – May 2 | — | — | 50–60 days | Fairly cold-hardy; direct sow 1-3 weeks before last frost. Tolerates light frost in fall too. |
| Broccoli | Mar 21 – Apr 4 | — | Apr 18 – Apr 25 | Aug 9 – Aug 16 | 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 21 – Apr 4 | — | Apr 25 – May 2 | Aug 2 – Aug 9 | 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 21 – Apr 4 | — | Apr 11 – Apr 25 | Aug 2 – Aug 16 | 60–100 days | Cold-hardy; start indoors 5-7 weeks before last frost, transplant 2-4 weeks before last frost. |
| Brussels Sprouts | Mar 21 – Apr 4 | — | Apr 18 – May 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 | — | Apr 11 – Apr 25 | — | Jul 19 – Aug 2 | 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 11 – Apr 25 | — | Aug 2 – Aug 16 | 50–65 days | Direct sow 2-4 weeks before last frost; tolerates light frost. |
| Radish | — | Apr 4 – Apr 18 | — | Aug 30 – Sep 13 | 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 11 – Apr 25 | — | Aug 2 – Aug 16 | 40–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. |
| Onion | Feb 28 – Mar 14 | — | Apr 11 – Apr 25 | — | 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 | — | — | — | Sep 13 – Sep 27 | 240–270 days | Fall-planted crop only; not planted in spring in most climates. |
| Potato | — | Apr 11 – Apr 25 | — | — | 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 | — | — | May 23 – Jun 6 | — | 90–120 days | Set out slips 2-4 weeks after last frost once soil is thoroughly warm (65F+); very frost/cold sensitive. |
| Asparagus | — | — | Apr 11 – Apr 25 | — | 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 | Mar 28 – Apr 4 | — | May 16 – May 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 | — | Apr 18 – May 2 | — | Aug 16 – Aug 30 | 45–70 days | Cool-season, bolts in heat; direct sow 1-3 weeks before last frost, succession sow through spring. |
| Parsley | Mar 14 – Mar 28 | — | Apr 25 – May 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 | — | Apr 18 – May 2 | — | — | 40–60 days | Taprooted, does not transplant well; direct sow 1-3 weeks before last frost, succession sow through summer. |
| Oregano | Mar 14 – Mar 28 | — | May 9 – May 16 | — | 80–90 days | Perennial herb; start indoors 6-8 weeks before last frost, transplant around/just after last frost date. |
| Thyme | Mar 14 – Mar 28 | — | May 9 – May 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 | — | May 16 – May 30 | — | — | 70–100 days | Direct sow 1-3 weeks after last frost once soil has warmed; taprooted, resents transplanting. |
| Zinnia | Apr 11 – Apr 18 | May 16 – May 30 | May 16 – May 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 | Mar 28 – Apr 11 | — | May 16 – May 23 | — | 45–60 days | Frost-tender; start indoors 4-6 weeks before last frost, transplant after all frost danger has passed. |
| Cosmos | Apr 11 – Apr 18 | May 16 – May 30 | May 16 – May 23 | — | 60–90 days | Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early. |
| Nasturtium | — | May 16 – May 30 | — | — | 50–65 days | Frost-tender, resents root disturbance; direct sow 1-3 weeks after last frost once soil has warmed. |
| Dahlia | — | — | May 16 – May 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 Sault Ste. Marie, MI?
Based on 1991–2020 NOAA climate normals for the SAULT STE MARIE SANDERSON FLD, MI US station, the last spring frost in Sault Ste. Marie typically falls around May 9. A cautious gardener might wait until May 27 (only a 10% chance of a later frost), while April 27 marks an earlier, higher-risk planting date.
When is the first frost in Sault Ste. Marie, MI in fall?
The first fall frost in Sault Ste. Marie typically arrives around October 11. To stay safe, assume frost could start as early as September 26; in milder years it can hold off until October 26.
How long is the growing season in Sault Ste. Marie, MI?
Sault Ste. Marie's average frost-free growing season is about 151 days, running from the typical last spring frost (May 9) to the typical first fall frost (October 11).
What USDA hardiness zone is Sault Ste. Marie, MI in?
Sault Ste. Marie, MI is in USDA plant hardiness zone 4b, per the USDA's 2023 Plant Hardiness Zone Map. Very cold winters, focus on short-season varieties and cold-hardy perennials.