Frost Dates for Polson, MT 59860
Last spring frost May 11 · First fall frost October 2 · 144 frost-free days · USDA Zone 6a
ZIP 59860 has about 11,900 people.
Moderate season: 144 frost-free days. Spring frost risk spans April 22–May 24 (32 days). Fall frost risk spans September 16–October 17 (31 days).
Frost probability for 59860
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 24 | May 11 | April 22 |
| Fall (first frost) | September 16 | October 2 | October 17 |
Dates come from NOAA 1971–2000 freeze probabilities at SKQ DAM (6.2 km away); the 50% date is the median year.
Which crops fit a 144-day season in Polson
In Polson (144 frost-free days, a moderate season), 38 of 56 planner crops fit outright, 17 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Apr 6 | May 25–Jun 1 | 102 | fits: 80 days to maturity, 102 available after May 25. | Jun 2 |
| Pepper | Mar 30 | May 25–Jun 1 | 102 | fits: 75 days to maturity, 102 available after May 25. | Jun 7 |
| Lettuce | Mar 16 | Apr 13–Apr 20 | 179 | two-plantings: Plant Apr 13 and again by Aug 11; both mature before Oct 9. | Aug 11 |
| Carrots | — | Apr 20–Apr 27 | 186 | fits: 70 days to maturity, 186 available after Apr 20. | Jul 31 |
| Cucumber | Apr 20 | May 25–Jun 1 | 116 | fits: 60 days to maturity, 116 available after May 25. | Jul 6 |
| Beans | — | May 18–Jun 1 | 130 | fits: 60 days to maturity, 130 available after May 18. | Jul 13 |
| Peas | — | Mar 16–May 25 | 207 | fits: 65 days to maturity, 207 available after Mar 16. | Jul 22 |
| Zucchini | Apr 27 | May 25–Jun 1 | 116 | fits: 55 days to maturity, 116 available after May 25. | Jul 11 |
| Onion | Feb 16 | Apr 13–Apr 27 | 179 | fits: 100 days to maturity, 179 available after Apr 13. | — |
| Spinach | — | Mar 16–May 4 | 221 | two-plantings: Plant Mar 16 and again by Aug 30; both mature before Oct 23. | Aug 30 |
| Kale | Mar 2 | Apr 13–Apr 27 | 193 | two-plantings: Plant Apr 13 and again by Aug 15; both mature before Oct 23. | Aug 15 |
| Broccoli | Mar 16 | Apr 13–Apr 27 | 179 | fits: 80 days to maturity, 179 available after Apr 13. | Jul 7 |
| Cabbage | Mar 16 | Apr 13–Apr 27 | 193 | fits: 70 days to maturity, 193 available after Apr 13. | Jul 31 |
| Radish | — | Mar 16–Jun 8 | 207 | two-plantings: Plant Mar 16 and again by Aug 31; both mature before Oct 9. | Aug 31 |
| Beets | — | Mar 16–Jun 8 | 207 | two-plantings: Plant Mar 16 and again by Aug 1; both mature before Oct 9. | Aug 1 |
| Potatoes | — | Apr 27–May 4 | 165 | fits: 90 days to maturity, 165 available after Apr 27. | — |
| Garlic | — | Oct 2 | 249 | overwinter: Plant Oct 2 to Oct 23; harvest the following summer. | Oct 23 |
| Strawberry | — | Apr 6–Jun 1 | 200 | perennial: A perennial: plant Apr 6; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 13 | May 18–May 25 | 116 | fits: 75 days to maturity, 116 available after May 18. | Jun 14 |
| Pumpkin | Apr 27 | May 25–May 25 | 109 | fits: 100 days to maturity, 109 available after May 25. | — |
| Cauliflower | Mar 30 | May 4–May 18 | 158 | fits: 75 days to maturity, 158 available after May 4. | Jul 12 |
| Swiss Chard | Mar 16 | Apr 27–Apr 27 | 165 | two-plantings: Plant Apr 27 and again by Aug 1; both mature before Oct 9. | Aug 1 |
| Arugula | — | Mar 16–Jun 8 | 221 | two-plantings: Plant Mar 16 and again by Aug 30; both mature before Oct 23. | Aug 30 |
| Brussel Sprouts | Mar 16 | Apr 13–Apr 27 | 193 | fits: 100 days to maturity, 193 available after Apr 13. | Jul 1 |
| Butternut Squash | Apr 27 | May 25–Jun 1 | 109 | fits: 100 days to maturity, 109 available after May 25. | — |
| Eggplant | Mar 23 | May 25–Jun 1 | 102 | fits: 70 days to maturity, 102 available after May 25. | Jun 12 |
| Okra | Apr 13 | May 18–May 25 | 123 | fits: 55 days to maturity, 123 available after May 18. | Jul 11 |
| Basil | Apr 6 | Jun 1–Jun 1 | 109 | fits: 60 days to maturity, 109 available after Jun 1. | Jul 6 |
| Cilantro | — | Apr 13–May 4 | 179 | two-plantings: Plant Apr 13 and again by Aug 6; both mature before Oct 9. | Aug 6 |
| Parsley | Mar 2 | May 18–May 25 | 144 | fits: 70 days to maturity, 144 available after May 18. | Jul 17 |
| Celery | Mar 2 | May 18–Jun 1 | 144 | fits: 120 days to maturity, 144 available after May 18. | May 28 |
| Scallions | Mar 2 | Apr 13–Apr 27 | 193 | two-plantings: Plant Apr 13 and again by Aug 10; both mature before Oct 23. | Aug 10 |
| Turnip | — | Apr 13–Apr 27 | 193 | two-plantings: Plant Apr 13 and again by Aug 20; both mature before Oct 23. | Aug 20 |
| Kohlrabi | — | Mar 30–Apr 13 | 207 | two-plantings: Plant Mar 30 and again by Aug 15; both mature before Oct 23. | Aug 15 |
| Bok Choy | Apr 13 | May 4–May 11 | 158 | two-plantings: Plant May 4 and again by Aug 11; both mature before Oct 9. | Aug 11 |
| Collards | Mar 2 | Apr 13–Apr 27 | 193 | two-plantings: Plant Apr 13 and again by Aug 10; both mature before Oct 23. | Aug 10 |
| Cantaloupe | Apr 27 | May 25–Jun 1 | 102 | fits: 85 days to maturity, 102 available after May 25. | May 28 |
| Chives | Feb 16 | May 18–May 25 | 158 | fits: 90 days to maturity, 158 available after May 18. | — |
| Dill | — | Mar 16–Jun 8 | 207 | two-plantings: Plant Mar 16 and again by Aug 1; both mature before Oct 9. | Aug 1 |
| Oregano | Mar 2 | May 18–May 25 | 158 | fits: 80 days to maturity, 158 available after May 18. | — |
| Rosemary | Feb 16 | May 18–May 25 | 144 | fits: 80 days to maturity, 144 available after May 18. | — |
| Sage | Mar 16 | May 18–May 25 | 158 | fits: 75 days to maturity, 158 available after May 18. | — |
| Thyme | Mar 2 | May 18–May 25 | 158 | fits: 90 days to maturity, 158 available after May 18. | — |
| Calendula | Mar 30 | Apr 27–May 11 | 165 | two-plantings: Plant Apr 27 and again by Aug 6; both mature before Oct 9. | Aug 6 |
| Cosmos | Apr 13 | May 11–May 25 | 130 | fits: 60 days to maturity, 130 available after May 11. | Jul 6 |
| Lavender | Feb 16 | May 11–May 25 | 165 | fits: 90 days to maturity, 165 available after May 11. | — |
| Marigolds | Mar 30 | May 11–May 18 | 130 | two-plantings: Plant May 11 and again by Jul 16; both mature before Sep 18. | Jul 16 |
| Melons | Apr 27 | May 25–Jun 1 | 102 | fits: 85 days to maturity, 102 available after May 25. | May 28 |
| Mint | — | May 11–May 25 | 165 | fits: 90 days to maturity, 165 available after May 11. | — |
| Nasturtiums | Apr 13 | May 11–May 18 | 130 | two-plantings: Plant May 11 and again by Jul 11; both mature before Sep 18. | Jul 11 |
| Pole Beans | — | May 18–Jun 1 | 123 | fits: 65 days to maturity, 123 available after May 18. | Jul 1 |
| Spaghetti Squash | Apr 27 | May 25–Jun 1 | 109 | fits: 90 days to maturity, 109 available after May 25. | May 30 |
| Sunflowers | — | May 11–May 25 | 130 | fits: 70 days to maturity, 130 available after May 11. | Jun 26 |
| Tomatillos | Mar 16 | May 18–May 25 | 109 | fits: 75 days to maturity, 109 available after May 18. | Jun 7 |
| Watermelon | Apr 27 | May 18–May 25 | 109 | fits: 80 days to maturity, 109 available after May 18. | Jun 2 |
| Yellow Squash | Apr 27 | May 25–Jun 1 | 116 | fits: 55 days to maturity, 116 available after May 25. | Jul 11 |
| Zinnias | Apr 13 | May 11–May 25 | 130 | fits: 60 days to maturity, 130 available after May 11. | Jul 6 |
Month by month in Polson
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 16), Lavender (Feb 16), Onion (Feb 16), Rosemary (Feb 16). |
| March | Start indoors: Celery (Mar 2), Collards (Mar 2), Kale (Mar 2), Oregano (Mar 2), Parsley (Mar 2), Scallions (Mar 2), +13 more. Direct sow from: Arugula (Mar 16), Beets (Mar 16), Dill (Mar 16), Peas (Mar 16), Radish (Mar 16), Spinach (Mar 16), +1 more. |
| April | Start indoors: Basil (Apr 6), Tomato (Apr 6), Bok Choy (Apr 13), Corn (Apr 13), Cosmos (Apr 13), Nasturtiums (Apr 13), +11 more. Direct sow from: Cilantro (Apr 13), Turnip (Apr 13), Carrots (Apr 20), Potatoes (Apr 27). Transplant from: Broccoli (Apr 13), Brussel Sprouts (Apr 13), Cabbage (Apr 13), Collards (Apr 13), Kale (Apr 13), Lettuce (Apr 13), +4 more. Plant: Strawberry (Apr 6). |
| May | Direct sow from: Sunflowers (May 11), Beans (May 18), Pole Beans (May 18). Transplant from: Bok Choy (May 4), Cauliflower (May 4), Cosmos (May 11), Lavender (May 11), Marigolds (May 11), Mint (May 11), +24 more. Last frost around May 11. Last sowing dates: Cantaloupe (May 28), Celery (May 28), Melons (May 28), Spaghetti Squash (May 30). |
| June | Transplant from: Basil (Jun 1). Last sowing dates: Tomato (Jun 2), Watermelon (Jun 2), Pepper (Jun 7), Tomatillos (Jun 7), Eggplant (Jun 12), Corn (Jun 14), +1 more. |
| July | Last sowing dates: Brussel Sprouts (Jul 1), Pole Beans (Jul 1), Basil (Jul 6), Cosmos (Jul 6), Cucumber (Jul 6), Zinnias (Jul 6), +12 more. |
| August | Last sowing dates: Beets (Aug 1), Dill (Aug 1), Swiss Chard (Aug 1), Calendula (Aug 6), Cilantro (Aug 6), Collards (Aug 10), +9 more. |
| September | First fall frost approaching (around October 2). Transplant fall brassicas. Sow spinach, arugula, and radishes. |
| October | Direct sow from: Garlic (Oct 2). First frost around October 2. Last sowing dates: Garlic (Oct 23). |
| November | Harvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year. |
| December | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
Frequently Asked Questions
What is the last frost date for Polson, MT (ZIP 59860)?
The median last spring frost date for Polson, MT (ZIP code 59860) is around May 11. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area. One year in ten frost ends before April 22; one in ten it runs past May 24.
What is the first fall frost date in Polson, MT?
The median first fall frost date for Polson, MT is around October 2. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses. The first frost arrives around September 16 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Polson, MT?
The frost-free growing season in Polson is about 144 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side. In Polson (144 frost-free days, a moderate season), 38 of 56 planner crops fit outright, 17 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Polson, MT?
Polson, MT is in USDA hardiness zone 6a (2023 USDA Plant Hardiness Zone Map). Zones come from the average coldest winter temperature, so they tell you which perennials survive the winter; the frost dates on this page tell you when to plant.
When should I start tomatoes indoors in Polson, MT?
Start tomatoes indoors Apr 6 and plant out May 25 in Polson. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Polson?
Two: plant Apr 13 and again by Aug 11; both mature before Oct 9.
When do I plant garlic in Polson?
Oct 2 to Oct 23; it overwinters and is ready the following summer.
Nearby and related
- Frost dates for Kalispell, MT 59901 (37.1 mi)
- Frost dates for Columbia Falls, MT 59912 (50.1 mi)
- Frost dates for Missoula, MT 59808 (50.9 mi)
- Frost dates for Whitefish, MT 59937 (52.2 mi)
- Frost dates for Missoula, MT 59801 (59.7 mi)
- When to plant in MT
- When to plant Peppers in MT
- When to plant Cucumbers in MT
- When to plant Zucchini in MT
- When to plant Butternut Squash in MT
- When to plant Basil in MT
- When to plant Sweet Corn in MT
- Look up another ZIP