Frost Dates for Spencer, IA 51301
Last spring frost April 30 · First fall frost September 29 · 152 frost-free days · USDA Zone 5a
ZIP 51301 has about 12,600 people.
Moderate season: 152 frost-free days. Spring frost risk spans April 17–May 13 (26 days). Fall frost risk spans September 17–October 11 (24 days).
Frost probability for 51301
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 13 | April 30 | April 17 |
| Fall (first frost) | September 17 | September 29 | October 11 |
Dates come from NOAA 1971–2000 freeze probabilities at MILFORD 4 NW (25.7 km away); the 50% date is the median year.
Which crops fit a 152-day season in Spencer
In Spencer (152 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 26 | May 14–May 21 | 110 | fits: 80 days to maturity, 110 available after May 14. | May 30 |
| Pepper | Mar 19 | May 14–May 21 | 110 | fits: 75 days to maturity, 110 available after May 14. | Jun 4 |
| Lettuce | Mar 5 | Apr 2–Apr 9 | 187 | two-plantings: Plant Apr 2 and again by Aug 8; both mature before Oct 6. | Aug 8 |
| Carrots | — | Apr 9–Apr 16 | 194 | fits: 70 days to maturity, 194 available after Apr 9. | Jul 28 |
| Cucumber | Apr 9 | May 14–May 21 | 124 | fits: 60 days to maturity, 124 available after May 14. | Jul 3 |
| Beans | — | May 7–May 21 | 138 | two-plantings: Plant May 7 and again by Jul 10; both mature before Sep 22. | Jul 10 |
| Peas | — | Mar 5–May 14 | 215 | fits: 65 days to maturity, 215 available after Mar 5. | Jul 19 |
| Zucchini | Apr 16 | May 14–May 21 | 124 | two-plantings: Plant May 14 and again by Jul 8; both mature before Sep 15. | Jul 8 |
| Onion | Feb 5 | Apr 2–Apr 16 | 187 | fits: 100 days to maturity, 187 available after Apr 2. | — |
| Spinach | — | Mar 5–Apr 23 | 229 | two-plantings: Plant Mar 5 and again by Aug 27; both mature before Oct 20. | Aug 27 |
| Kale | Feb 19 | Apr 2–Apr 16 | 201 | two-plantings: Plant Apr 2 and again by Aug 12; both mature before Oct 20. | Aug 12 |
| Broccoli | Mar 5 | Apr 2–Apr 16 | 187 | fits: 80 days to maturity, 187 available after Apr 2. | Jul 4 |
| Cabbage | Mar 5 | Apr 2–Apr 16 | 201 | fits: 70 days to maturity, 201 available after Apr 2. | Jul 28 |
| Radish | — | Mar 5–May 28 | 215 | two-plantings: Plant Mar 5 and again by Aug 28; both mature before Oct 6. | Aug 28 |
| Beets | — | Mar 5–May 28 | 215 | two-plantings: Plant Mar 5 and again by Jul 29; both mature before Oct 6. | Jul 29 |
| Potatoes | — | Apr 16–Apr 23 | 173 | fits: 90 days to maturity, 173 available after Apr 16. | — |
| Garlic | — | Sep 29 | 257 | overwinter: Plant Sep 29 to Oct 20; harvest the following summer. | Oct 20 |
| Strawberry | — | Mar 26–May 21 | 208 | perennial: A perennial: plant Mar 26; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 2 | May 7–May 14 | 124 | fits: 75 days to maturity, 124 available after May 7. | Jun 11 |
| Pumpkin | Apr 16 | May 14–May 14 | 117 | fits: 100 days to maturity, 117 available after May 14. | May 17 |
| Cauliflower | Mar 19 | Apr 23–May 7 | 166 | fits: 75 days to maturity, 166 available after Apr 23. | Jul 9 |
| Swiss Chard | Mar 5 | Apr 16–Apr 16 | 173 | two-plantings: Plant Apr 16 and again by Jul 29; both mature before Oct 6. | Jul 29 |
| Arugula | — | Mar 5–May 28 | 229 | two-plantings: Plant Mar 5 and again by Aug 27; both mature before Oct 20. | Aug 27 |
| Brussel Sprouts | Mar 5 | Apr 2–Apr 16 | 201 | fits: 100 days to maturity, 201 available after Apr 2. | Jun 28 |
| Butternut Squash | Apr 16 | May 14–May 21 | 117 | fits: 100 days to maturity, 117 available after May 14. | May 17 |
| Eggplant | Mar 12 | May 14–May 21 | 110 | fits: 70 days to maturity, 110 available after May 14. | Jun 9 |
| Okra | Apr 2 | May 7–May 14 | 131 | two-plantings: Plant May 7 and again by Jul 8; both mature before Sep 15. | Jul 8 |
| Basil | Mar 26 | May 21–May 21 | 117 | fits: 60 days to maturity, 117 available after May 21. | Jul 3 |
| Cilantro | — | Apr 2–Apr 23 | 187 | two-plantings: Plant Apr 2 and again by Aug 3; both mature before Oct 6. | Aug 3 |
| Parsley | Feb 19 | May 7–May 14 | 152 | fits: 70 days to maturity, 152 available after May 7. | Jul 14 |
| Celery | Feb 19 | May 7–May 21 | 152 | fits: 120 days to maturity, 152 available after May 7. | May 25 |
| Scallions | Feb 19 | Apr 2–Apr 16 | 201 | two-plantings: Plant Apr 2 and again by Aug 7; both mature before Oct 20. | Aug 7 |
| Turnip | — | Apr 2–Apr 16 | 201 | two-plantings: Plant Apr 2 and again by Aug 17; both mature before Oct 20. | Aug 17 |
| Kohlrabi | — | Mar 19–Apr 2 | 215 | two-plantings: Plant Mar 19 and again by Aug 12; both mature before Oct 20. | Aug 12 |
| Bok Choy | Apr 2 | Apr 23–Apr 30 | 166 | two-plantings: Plant Apr 23 and again by Aug 8; both mature before Oct 6. | Aug 8 |
| Collards | Feb 19 | Apr 2–Apr 16 | 201 | two-plantings: Plant Apr 2 and again by Aug 7; both mature before Oct 20. | Aug 7 |
| Cantaloupe | Apr 16 | May 14–May 21 | 110 | fits: 85 days to maturity, 110 available after May 14. | May 25 |
| Chives | Feb 5 | May 7–May 14 | 166 | fits: 90 days to maturity, 166 available after May 7. | — |
| Dill | — | Mar 5–May 28 | 215 | two-plantings: Plant Mar 5 and again by Jul 29; both mature before Oct 6. | Jul 29 |
| Oregano | Feb 19 | May 7–May 14 | 166 | fits: 80 days to maturity, 166 available after May 7. | — |
| Rosemary | Feb 5 | May 7–May 14 | 152 | fits: 80 days to maturity, 152 available after May 7. | — |
| Sage | Mar 5 | May 7–May 14 | 166 | fits: 75 days to maturity, 166 available after May 7. | — |
| Thyme | Feb 19 | May 7–May 14 | 166 | fits: 90 days to maturity, 166 available after May 7. | — |
| Calendula | Mar 19 | Apr 16–Apr 30 | 173 | two-plantings: Plant Apr 16 and again by Aug 3; both mature before Oct 6. | Aug 3 |
| Cosmos | Apr 2 | Apr 30–May 14 | 138 | two-plantings: Plant Apr 30 and again by Jul 3; both mature before Sep 15. | Jul 3 |
| Lavender | Feb 5 | Apr 30–May 14 | 173 | fits: 90 days to maturity, 173 available after Apr 30. | — |
| Marigolds | Mar 19 | Apr 30–May 7 | 138 | two-plantings: Plant Apr 30 and again by Jul 13; both mature before Sep 15. | Jul 13 |
| Melons | Apr 16 | May 14–May 21 | 110 | fits: 85 days to maturity, 110 available after May 14. | May 25 |
| Mint | — | Apr 30–May 14 | 173 | fits: 90 days to maturity, 173 available after Apr 30. | — |
| Nasturtiums | Apr 2 | Apr 30–May 7 | 138 | two-plantings: Plant Apr 30 and again by Jul 8; both mature before Sep 15. | Jul 8 |
| Pole Beans | — | May 7–May 21 | 131 | fits: 65 days to maturity, 131 available after May 7. | Jun 28 |
| Spaghetti Squash | Apr 16 | May 14–May 21 | 117 | fits: 90 days to maturity, 117 available after May 14. | May 27 |
| Sunflowers | — | Apr 30–May 14 | 138 | fits: 70 days to maturity, 138 available after Apr 30. | Jun 23 |
| Tomatillos | Mar 5 | May 7–May 14 | 117 | fits: 75 days to maturity, 117 available after May 7. | Jun 4 |
| Watermelon | Apr 16 | May 7–May 14 | 117 | fits: 80 days to maturity, 117 available after May 7. | May 30 |
| Yellow Squash | Apr 16 | May 14–May 21 | 124 | two-plantings: Plant May 14 and again by Jul 8; both mature before Sep 15. | Jul 8 |
| Zinnias | Apr 2 | Apr 30–May 14 | 138 | two-plantings: Plant Apr 30 and again by Jul 3; both mature before Sep 15. | Jul 3 |
Month by month in Spencer
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 5), Lavender (Feb 5), Onion (Feb 5), Rosemary (Feb 5), Celery (Feb 19), Collards (Feb 19), +5 more. |
| March | Start indoors: Broccoli (Mar 5), Brussel Sprouts (Mar 5), Cabbage (Mar 5), Lettuce (Mar 5), Sage (Mar 5), Swiss Chard (Mar 5), +8 more. Direct sow from: Arugula (Mar 5), Beets (Mar 5), Dill (Mar 5), Peas (Mar 5), Radish (Mar 5), Spinach (Mar 5), +1 more. Plant: Strawberry (Mar 26). |
| April | Start indoors: Bok Choy (Apr 2), Corn (Apr 2), Cosmos (Apr 2), Nasturtiums (Apr 2), Okra (Apr 2), Zinnias (Apr 2), +9 more. Direct sow from: Cilantro (Apr 2), Turnip (Apr 2), Carrots (Apr 9), Potatoes (Apr 16), Sunflowers (Apr 30). Transplant from: Broccoli (Apr 2), Brussel Sprouts (Apr 2), Cabbage (Apr 2), Collards (Apr 2), Kale (Apr 2), Lettuce (Apr 2), +12 more. Last frost around April 30. |
| May | Direct sow from: Beans (May 7), Pole Beans (May 7). Transplant from: Celery (May 7), Chives (May 7), Corn (May 7), Okra (May 7), Oregano (May 7), Parsley (May 7), +17 more. Last sowing dates: Butternut Squash (May 17), Pumpkin (May 17), Cantaloupe (May 25), Celery (May 25), Melons (May 25), Spaghetti Squash (May 27), +2 more. |
| June | Last sowing dates: Pepper (Jun 4), Tomatillos (Jun 4), Eggplant (Jun 9), Corn (Jun 11), Sunflowers (Jun 23), Brussel Sprouts (Jun 28), +1 more. |
| July | Last sowing dates: Basil (Jul 3), Cosmos (Jul 3), Cucumber (Jul 3), Zinnias (Jul 3), Broccoli (Jul 4), Nasturtiums (Jul 8), +13 more. |
| August | Last sowing dates: Calendula (Aug 3), Cilantro (Aug 3), Collards (Aug 7), Scallions (Aug 7), Bok Choy (Aug 8), Lettuce (Aug 8), +6 more. |
| September | Direct sow from: Garlic (Sep 29). First frost around September 29. |
| October | Last sowing dates: Garlic (Oct 20). |
| November | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
| 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 Spencer, IA (ZIP 51301)?
The median last spring frost date for Spencer, IA (ZIP code 51301) is around April 30. 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 17; one in ten it runs past May 13.
What is the first fall frost date in Spencer, IA?
The median first fall frost date for Spencer, IA is around September 29. 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 17 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Spencer, IA?
The frost-free growing season in Spencer is about 152 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 Spencer (152 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 Spencer, IA?
Spencer, 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 Spencer, IA?
Start tomatoes indoors Mar 26 and plant out May 14 in Spencer. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Spencer?
Two: plant Apr 2 and again by Aug 8; both mature before Oct 6.
When do I plant garlic in Spencer?
Sep 29 to Oct 20; it overwinters and is ready the following summer.
Which nearby ZIP has a longer season?
Fairmont (ZIP 56031) has 159 frost-free days, 7 more than Spencer (ZIP 51301). See Fairmont ZIP 56031 frost dates
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