Frost Dates for Carroll, IA 51401
Last spring frost April 28 · First fall frost October 3 · 158 frost-free days · USDA Zone 5a
ZIP 51401 has about 12,000 people.
Moderate season: 158 frost-free days. Spring frost risk spans April 15–May 12 (27 days). Fall frost risk spans September 18–October 17 (29 days).
Frost probability for 51401
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 12 | April 28 | April 15 |
| Fall (first frost) | September 18 | October 3 | October 17 |
Dates come from NOAA 1971–2000 freeze probabilities at AUDUBON (40.1 km away); the 50% date is the median year.
Which crops fit a 158-day season in Carroll
In Carroll (158 frost-free days, a moderate season), 32 of 56 planner crops fit outright, 23 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 24 | May 12–May 19 | 116 | fits: 80 days to maturity, 116 available after May 12. | Jun 3 |
| Pepper | Mar 17 | May 12–May 19 | 116 | fits: 75 days to maturity, 116 available after May 12. | Jun 8 |
| Lettuce | Mar 3 | Mar 31–Apr 7 | 193 | two-plantings: Plant Mar 31 and again by Aug 12; both mature before Oct 10. | Aug 12 |
| Carrots | — | Apr 7–Apr 14 | 200 | fits: 70 days to maturity, 200 available after Apr 7. | Aug 1 |
| Cucumber | Apr 7 | May 12–May 19 | 130 | fits: 60 days to maturity, 130 available after May 12. | Jul 7 |
| Beans | — | May 5–May 19 | 144 | two-plantings: Plant May 5 and again by Jul 14; both mature before Sep 26. | Jul 14 |
| Peas | — | Mar 3–May 12 | 221 | fits: 65 days to maturity, 221 available after Mar 3. | Jul 23 |
| Zucchini | Apr 14 | May 12–May 19 | 130 | two-plantings: Plant May 12 and again by Jul 12; both mature before Sep 19. | Jul 12 |
| Onion | Feb 3 | Mar 31–Apr 14 | 193 | fits: 100 days to maturity, 193 available after Mar 31. | — |
| Spinach | — | Mar 3–Apr 21 | 235 | two-plantings: Plant Mar 3 and again by Aug 31; both mature before Oct 24. | Aug 31 |
| Kale | Feb 17 | Mar 31–Apr 14 | 207 | two-plantings: Plant Mar 31 and again by Aug 16; both mature before Oct 24. | Aug 16 |
| Broccoli | Mar 3 | Mar 31–Apr 14 | 193 | fits: 80 days to maturity, 193 available after Mar 31. | Jul 8 |
| Cabbage | Mar 3 | Mar 31–Apr 14 | 207 | fits: 70 days to maturity, 207 available after Mar 31. | Aug 1 |
| Radish | — | Mar 3–May 26 | 221 | two-plantings: Plant Mar 3 and again by Sep 1; both mature before Oct 10. | Sep 1 |
| Beets | — | Mar 3–May 26 | 221 | two-plantings: Plant Mar 3 and again by Aug 2; both mature before Oct 10. | Aug 2 |
| Potatoes | — | Apr 14–Apr 21 | 179 | fits: 90 days to maturity, 179 available after Apr 14. | — |
| Garlic | — | Oct 3 | 263 | overwinter: Plant Oct 3 to Oct 24; harvest the following summer. | Oct 24 |
| Strawberry | — | Mar 24–May 19 | 214 | perennial: A perennial: plant Mar 24; it fruits from the following year and keeps producing for several years. | — |
| Corn | Mar 31 | May 5–May 12 | 130 | fits: 75 days to maturity, 130 available after May 5. | Jun 15 |
| Pumpkin | Apr 14 | May 12–May 12 | 123 | fits: 100 days to maturity, 123 available after May 12. | May 21 |
| Cauliflower | Mar 17 | Apr 21–May 5 | 172 | fits: 75 days to maturity, 172 available after Apr 21. | Jul 13 |
| Swiss Chard | Mar 3 | Apr 14–Apr 14 | 179 | two-plantings: Plant Apr 14 and again by Aug 2; both mature before Oct 10. | Aug 2 |
| Arugula | — | Mar 3–May 26 | 235 | two-plantings: Plant Mar 3 and again by Aug 31; both mature before Oct 24. | Aug 31 |
| Brussel Sprouts | Mar 3 | Mar 31–Apr 14 | 207 | fits: 100 days to maturity, 207 available after Mar 31. | Jul 2 |
| Butternut Squash | Apr 14 | May 12–May 19 | 123 | fits: 100 days to maturity, 123 available after May 12. | May 21 |
| Eggplant | Mar 10 | May 12–May 19 | 116 | fits: 70 days to maturity, 116 available after May 12. | Jun 13 |
| Okra | Mar 31 | May 5–May 12 | 137 | two-plantings: Plant May 5 and again by Jul 12; both mature before Sep 19. | Jul 12 |
| Basil | Mar 24 | May 19–May 19 | 123 | fits: 60 days to maturity, 123 available after May 19. | Jul 7 |
| Cilantro | — | Mar 31–Apr 21 | 193 | two-plantings: Plant Mar 31 and again by Aug 7; both mature before Oct 10. | Aug 7 |
| Parsley | Feb 17 | May 5–May 12 | 158 | fits: 70 days to maturity, 158 available after May 5. | Jul 18 |
| Celery | Feb 17 | May 5–May 19 | 158 | fits: 120 days to maturity, 158 available after May 5. | May 29 |
| Scallions | Feb 17 | Mar 31–Apr 14 | 207 | two-plantings: Plant Mar 31 and again by Aug 11; both mature before Oct 24. | Aug 11 |
| Turnip | — | Mar 31–Apr 14 | 207 | two-plantings: Plant Mar 31 and again by Aug 21; both mature before Oct 24. | Aug 21 |
| Kohlrabi | — | Mar 17–Mar 31 | 221 | two-plantings: Plant Mar 17 and again by Aug 16; both mature before Oct 24. | Aug 16 |
| Bok Choy | Mar 31 | Apr 21–Apr 28 | 172 | two-plantings: Plant Apr 21 and again by Aug 12; both mature before Oct 10. | Aug 12 |
| Collards | Feb 17 | Mar 31–Apr 14 | 207 | two-plantings: Plant Mar 31 and again by Aug 11; both mature before Oct 24. | Aug 11 |
| Cantaloupe | Apr 14 | May 12–May 19 | 116 | fits: 85 days to maturity, 116 available after May 12. | May 29 |
| Chives | Feb 3 | May 5–May 12 | 172 | fits: 90 days to maturity, 172 available after May 5. | — |
| Dill | — | Mar 3–May 26 | 221 | two-plantings: Plant Mar 3 and again by Aug 2; both mature before Oct 10. | Aug 2 |
| Oregano | Feb 17 | May 5–May 12 | 172 | fits: 80 days to maturity, 172 available after May 5. | — |
| Rosemary | Feb 3 | May 5–May 12 | 158 | fits: 80 days to maturity, 158 available after May 5. | — |
| Sage | Mar 3 | May 5–May 12 | 172 | fits: 75 days to maturity, 172 available after May 5. | — |
| Thyme | Feb 17 | May 5–May 12 | 172 | fits: 90 days to maturity, 172 available after May 5. | — |
| Calendula | Mar 17 | Apr 14–Apr 28 | 179 | two-plantings: Plant Apr 14 and again by Aug 7; both mature before Oct 10. | Aug 7 |
| Cosmos | Mar 31 | Apr 28–May 12 | 144 | two-plantings: Plant Apr 28 and again by Jul 7; both mature before Sep 19. | Jul 7 |
| Lavender | Feb 3 | Apr 28–May 12 | 179 | fits: 90 days to maturity, 179 available after Apr 28. | — |
| Marigolds | Mar 17 | Apr 28–May 5 | 144 | two-plantings: Plant Apr 28 and again by Jul 17; both mature before Sep 19. | Jul 17 |
| Melons | Apr 14 | May 12–May 19 | 116 | fits: 85 days to maturity, 116 available after May 12. | May 29 |
| Mint | — | Apr 28–May 12 | 179 | fits: 90 days to maturity, 179 available after Apr 28. | — |
| Nasturtiums | Mar 31 | Apr 28–May 5 | 144 | two-plantings: Plant Apr 28 and again by Jul 12; both mature before Sep 19. | Jul 12 |
| Pole Beans | — | May 5–May 19 | 137 | fits: 65 days to maturity, 137 available after May 5. | Jul 2 |
| Spaghetti Squash | Apr 14 | May 12–May 19 | 123 | fits: 90 days to maturity, 123 available after May 12. | May 31 |
| Sunflowers | — | Apr 28–May 12 | 144 | fits: 70 days to maturity, 144 available after Apr 28. | Jun 27 |
| Tomatillos | Mar 3 | May 5–May 12 | 123 | fits: 75 days to maturity, 123 available after May 5. | Jun 8 |
| Watermelon | Apr 14 | May 5–May 12 | 123 | fits: 80 days to maturity, 123 available after May 5. | Jun 3 |
| Yellow Squash | Apr 14 | May 12–May 19 | 130 | two-plantings: Plant May 12 and again by Jul 12; both mature before Sep 19. | Jul 12 |
| Zinnias | Mar 31 | Apr 28–May 12 | 144 | two-plantings: Plant Apr 28 and again by Jul 7; both mature before Sep 19. | Jul 7 |
Month by month in Carroll
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 3), Lavender (Feb 3), Onion (Feb 3), Rosemary (Feb 3), Celery (Feb 17), Collards (Feb 17), +5 more. |
| March | Start indoors: Broccoli (Mar 3), Brussel Sprouts (Mar 3), Cabbage (Mar 3), Lettuce (Mar 3), Sage (Mar 3), Swiss Chard (Mar 3), +14 more. Direct sow from: Arugula (Mar 3), Beets (Mar 3), Dill (Mar 3), Peas (Mar 3), Radish (Mar 3), Spinach (Mar 3), +3 more. Transplant from: Broccoli (Mar 31), Brussel Sprouts (Mar 31), Cabbage (Mar 31), Collards (Mar 31), Kale (Mar 31), Lettuce (Mar 31), +2 more. Plant: Strawberry (Mar 24). |
| April | Start indoors: Cucumber (Apr 7), Butternut Squash (Apr 14), Cantaloupe (Apr 14), Melons (Apr 14), Pumpkin (Apr 14), Spaghetti Squash (Apr 14), +3 more. Direct sow from: Carrots (Apr 7), Potatoes (Apr 14), Sunflowers (Apr 28). Transplant from: Calendula (Apr 14), Swiss Chard (Apr 14), Bok Choy (Apr 21), Cauliflower (Apr 21), Cosmos (Apr 28), Lavender (Apr 28), +4 more. Last frost around April 28. |
| May | Direct sow from: Beans (May 5), Pole Beans (May 5). Transplant from: Celery (May 5), Chives (May 5), Corn (May 5), Okra (May 5), Oregano (May 5), Parsley (May 5), +17 more. 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 Carroll, IA (ZIP 51401)?
The median last spring frost date for Carroll, IA (ZIP code 51401) is around April 28. 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 15; one in ten it runs past May 12.
What is the first fall frost date in Carroll, IA?
The median first fall frost date for Carroll, 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 18 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Carroll, IA?
The frost-free growing season in Carroll is about 158 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 Carroll (158 frost-free days, a moderate season), 32 of 56 planner crops fit outright, 23 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Carroll, IA?
Carroll, 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 Carroll, IA?
Start tomatoes indoors Mar 24 and plant out May 12 in Carroll. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Carroll?
Two: plant Mar 31 and again by Aug 12; both mature before Oct 10.
When do I plant garlic in Carroll?
Oct 3 to Oct 24; it overwinters and is ready the following summer.
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