Frost Dates for Decorah, IA 52101
Last spring frost May 5 · First fall frost October 3 · 151 frost-free days · USDA Zone 5a
ZIP 52101 has about 12,700 people.
Moderate season: 151 frost-free days. Spring frost risk spans April 21–May 19 (28 days). Fall frost risk spans September 22–October 15 (23 days).
Frost probability for 52101
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 19 | May 5 | April 21 |
| Fall (first frost) | September 22 | October 3 | October 15 |
Dates come from NOAA 1971–2000 freeze probabilities at DECORAH (6.4 km away); the 50% date is the median year.
Which crops fit a 151-day season in Decorah
In Decorah (151 frost-free days, a moderate season), 34 of 56 planner crops fit outright, 21 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 31 | May 19–May 26 | 109 | fits: 80 days to maturity, 109 available after May 19. | Jun 3 |
| Pepper | Mar 24 | May 19–May 26 | 109 | fits: 75 days to maturity, 109 available after May 19. | Jun 8 |
| Lettuce | Mar 10 | Apr 7–Apr 14 | 186 | two-plantings: Plant Apr 7 and again by Aug 12; both mature before Oct 10. | Aug 12 |
| Carrots | — | Apr 14–Apr 21 | 193 | fits: 70 days to maturity, 193 available after Apr 14. | Aug 1 |
| Cucumber | Apr 14 | May 19–May 26 | 123 | fits: 60 days to maturity, 123 available after May 19. | Jul 7 |
| Beans | — | May 12–May 26 | 137 | two-plantings: Plant May 12 and again by Jul 14; both mature before Sep 26. | Jul 14 |
| Peas | — | Mar 10–May 19 | 214 | fits: 65 days to maturity, 214 available after Mar 10. | Jul 23 |
| Zucchini | Apr 21 | May 19–May 26 | 123 | fits: 55 days to maturity, 123 available after May 19. | Jul 12 |
| Onion | Feb 10 | Apr 7–Apr 21 | 186 | fits: 100 days to maturity, 186 available after Apr 7. | — |
| Spinach | — | Mar 10–Apr 28 | 228 | two-plantings: Plant Mar 10 and again by Aug 31; both mature before Oct 24. | Aug 31 |
| Kale | Feb 24 | Apr 7–Apr 21 | 200 | two-plantings: Plant Apr 7 and again by Aug 16; both mature before Oct 24. | Aug 16 |
| Broccoli | Mar 10 | Apr 7–Apr 21 | 186 | fits: 80 days to maturity, 186 available after Apr 7. | Jul 8 |
| Cabbage | Mar 10 | Apr 7–Apr 21 | 200 | fits: 70 days to maturity, 200 available after Apr 7. | Aug 1 |
| Radish | — | Mar 10–Jun 2 | 214 | two-plantings: Plant Mar 10 and again by Sep 1; both mature before Oct 10. | Sep 1 |
| Beets | — | Mar 10–Jun 2 | 214 | two-plantings: Plant Mar 10 and again by Aug 2; both mature before Oct 10. | Aug 2 |
| Potatoes | — | Apr 21–Apr 28 | 172 | fits: 90 days to maturity, 172 available after Apr 21. | — |
| Garlic | — | Oct 3 | 256 | overwinter: Plant Oct 3 to Oct 24; harvest the following summer. | Oct 24 |
| Strawberry | — | Mar 31–May 26 | 207 | perennial: A perennial: plant Mar 31; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 7 | May 12–May 19 | 123 | fits: 75 days to maturity, 123 available after May 12. | Jun 15 |
| Pumpkin | Apr 21 | May 19–May 19 | 116 | fits: 100 days to maturity, 116 available after May 19. | May 21 |
| Cauliflower | Mar 24 | Apr 28–May 12 | 165 | fits: 75 days to maturity, 165 available after Apr 28. | Jul 13 |
| Swiss Chard | Mar 10 | Apr 21–Apr 21 | 172 | two-plantings: Plant Apr 21 and again by Aug 2; both mature before Oct 10. | Aug 2 |
| Arugula | — | Mar 10–Jun 2 | 228 | two-plantings: Plant Mar 10 and again by Aug 31; both mature before Oct 24. | Aug 31 |
| Brussel Sprouts | Mar 10 | Apr 7–Apr 21 | 200 | fits: 100 days to maturity, 200 available after Apr 7. | Jul 2 |
| Butternut Squash | Apr 21 | May 19–May 26 | 116 | fits: 100 days to maturity, 116 available after May 19. | May 21 |
| Eggplant | Mar 17 | May 19–May 26 | 109 | fits: 70 days to maturity, 109 available after May 19. | Jun 13 |
| Okra | Apr 7 | May 12–May 19 | 130 | two-plantings: Plant May 12 and again by Jul 12; both mature before Sep 19. | Jul 12 |
| Basil | Mar 31 | May 26–May 26 | 116 | fits: 60 days to maturity, 116 available after May 26. | Jul 7 |
| Cilantro | — | Apr 7–Apr 28 | 186 | two-plantings: Plant Apr 7 and again by Aug 7; both mature before Oct 10. | Aug 7 |
| Parsley | Feb 24 | May 12–May 19 | 151 | fits: 70 days to maturity, 151 available after May 12. | Jul 18 |
| Celery | Feb 24 | May 12–May 26 | 151 | fits: 120 days to maturity, 151 available after May 12. | May 29 |
| Scallions | Feb 24 | Apr 7–Apr 21 | 200 | two-plantings: Plant Apr 7 and again by Aug 11; both mature before Oct 24. | Aug 11 |
| Turnip | — | Apr 7–Apr 21 | 200 | two-plantings: Plant Apr 7 and again by Aug 21; both mature before Oct 24. | Aug 21 |
| Kohlrabi | — | Mar 24–Apr 7 | 214 | two-plantings: Plant Mar 24 and again by Aug 16; both mature before Oct 24. | Aug 16 |
| Bok Choy | Apr 7 | Apr 28–May 5 | 165 | two-plantings: Plant Apr 28 and again by Aug 12; both mature before Oct 10. | Aug 12 |
| Collards | Feb 24 | Apr 7–Apr 21 | 200 | two-plantings: Plant Apr 7 and again by Aug 11; both mature before Oct 24. | Aug 11 |
| Cantaloupe | Apr 21 | May 19–May 26 | 109 | fits: 85 days to maturity, 109 available after May 19. | May 29 |
| Chives | Feb 10 | May 12–May 19 | 165 | fits: 90 days to maturity, 165 available after May 12. | — |
| Dill | — | Mar 10–Jun 2 | 214 | two-plantings: Plant Mar 10 and again by Aug 2; both mature before Oct 10. | Aug 2 |
| Oregano | Feb 24 | May 12–May 19 | 165 | fits: 80 days to maturity, 165 available after May 12. | — |
| Rosemary | Feb 10 | May 12–May 19 | 151 | fits: 80 days to maturity, 151 available after May 12. | — |
| Sage | Mar 10 | May 12–May 19 | 165 | fits: 75 days to maturity, 165 available after May 12. | — |
| Thyme | Feb 24 | May 12–May 19 | 165 | fits: 90 days to maturity, 165 available after May 12. | — |
| Calendula | Mar 24 | Apr 21–May 5 | 172 | two-plantings: Plant Apr 21 and again by Aug 7; both mature before Oct 10. | Aug 7 |
| Cosmos | Apr 7 | May 5–May 19 | 137 | two-plantings: Plant May 5 and again by Jul 7; both mature before Sep 19. | Jul 7 |
| Lavender | Feb 10 | May 5–May 19 | 172 | fits: 90 days to maturity, 172 available after May 5. | — |
| Marigolds | Mar 24 | May 5–May 12 | 137 | two-plantings: Plant May 5 and again by Jul 17; both mature before Sep 19. | Jul 17 |
| Melons | Apr 21 | May 19–May 26 | 109 | fits: 85 days to maturity, 109 available after May 19. | May 29 |
| Mint | — | May 5–May 19 | 172 | fits: 90 days to maturity, 172 available after May 5. | — |
| Nasturtiums | Apr 7 | May 5–May 12 | 137 | two-plantings: Plant May 5 and again by Jul 12; both mature before Sep 19. | Jul 12 |
| Pole Beans | — | May 12–May 26 | 130 | fits: 65 days to maturity, 130 available after May 12. | Jul 2 |
| Spaghetti Squash | Apr 21 | May 19–May 26 | 116 | fits: 90 days to maturity, 116 available after May 19. | May 31 |
| Sunflowers | — | May 5–May 19 | 137 | fits: 70 days to maturity, 137 available after May 5. | Jun 27 |
| Tomatillos | Mar 10 | May 12–May 19 | 116 | fits: 75 days to maturity, 116 available after May 12. | Jun 8 |
| Watermelon | Apr 21 | May 12–May 19 | 116 | fits: 80 days to maturity, 116 available after May 12. | Jun 3 |
| Yellow Squash | Apr 21 | May 19–May 26 | 123 | fits: 55 days to maturity, 123 available after May 19. | Jul 12 |
| Zinnias | Apr 7 | May 5–May 19 | 137 | two-plantings: Plant May 5 and again by Jul 7; both mature before Sep 19. | Jul 7 |
Month by month in Decorah
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 10), Lavender (Feb 10), Onion (Feb 10), Rosemary (Feb 10), Celery (Feb 24), Collards (Feb 24), +5 more. |
| March | Start indoors: Broccoli (Mar 10), Brussel Sprouts (Mar 10), Cabbage (Mar 10), Lettuce (Mar 10), Sage (Mar 10), Swiss Chard (Mar 10), +8 more. Direct sow from: Arugula (Mar 10), Beets (Mar 10), Dill (Mar 10), Peas (Mar 10), Radish (Mar 10), Spinach (Mar 10), +1 more. Plant: Strawberry (Mar 31). |
| April | Start indoors: Bok Choy (Apr 7), Corn (Apr 7), Cosmos (Apr 7), Nasturtiums (Apr 7), Okra (Apr 7), Zinnias (Apr 7), +9 more. Direct sow from: Cilantro (Apr 7), Turnip (Apr 7), Carrots (Apr 14), Potatoes (Apr 21). Transplant from: Broccoli (Apr 7), Brussel Sprouts (Apr 7), Cabbage (Apr 7), Collards (Apr 7), Kale (Apr 7), Lettuce (Apr 7), +6 more. |
| May | Direct sow from: Sunflowers (May 5), Beans (May 12), Pole Beans (May 12). Transplant from: Cosmos (May 5), Lavender (May 5), Marigolds (May 5), Mint (May 5), Nasturtiums (May 5), Zinnias (May 5), +23 more. Last frost around May 5. Last sowing dates: Butternut Squash (May 21), Pumpkin (May 21), Cantaloupe (May 29), Celery (May 29), Melons (May 29), Spaghetti Squash (May 31). |
| June | Last sowing dates: Tomato (Jun 3), Watermelon (Jun 3), Pepper (Jun 8), Tomatillos (Jun 8), Eggplant (Jun 13), Corn (Jun 15), +1 more. |
| July | Last sowing dates: Brussel Sprouts (Jul 2), Pole Beans (Jul 2), Basil (Jul 7), Cosmos (Jul 7), Cucumber (Jul 7), Zinnias (Jul 7), +10 more. |
| August | Last sowing dates: Cabbage (Aug 1), Carrots (Aug 1), Beets (Aug 2), Dill (Aug 2), Swiss Chard (Aug 2), Calendula (Aug 7), +10 more. |
| September | Last sowing dates: Radish (Sep 1). |
| October | Direct sow from: Garlic (Oct 3). First frost around October 3. Last sowing dates: Garlic (Oct 24). |
| 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 Decorah, IA (ZIP 52101)?
The median last spring frost date for Decorah, IA (ZIP code 52101) is around May 5. 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 21; one in ten it runs past May 19.
What is the first fall frost date in Decorah, IA?
The median first fall frost date for Decorah, IA is around October 3. 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 22 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Decorah, IA?
The frost-free growing season in Decorah is about 151 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 Decorah (151 frost-free days, a moderate season), 34 of 56 planner crops fit outright, 21 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Decorah, IA?
Decorah, IA is in USDA hardiness zone 5a (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 Decorah, IA?
Start tomatoes indoors Mar 31 and plant out May 19 in Decorah. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Decorah?
Two: plant Apr 7 and again by Aug 12; both mature before Oct 10.
When do I plant garlic in Decorah?
Oct 3 to Oct 24; it overwinters and is ready the following summer.
Which nearby ZIP has a longer season?
La Crosse (ZIP 54601) has 164 frost-free days, 13 more than Decorah (ZIP 52101). See La Crosse ZIP 54601 frost dates
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